The Triumph Dolomite Club - Discussion Forum

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PostPosted:Wed Jun 29, 2022 4:54 pm 
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Location:South Benfleet, Essex
Quote:
I've had numerous sets of different wheels in differing sizes on my Dolomites. 185/55x15s on anything are awful, far too heavy making every response of the car lumpen. I can only imagine 195/55x16 being even worse, don't do it, Nigel!

On 13s I like 175/65 or 185/60, on 14s 185/50 seem best, but Michelins in 175/55 work well too, on 15s I've got away with 195/45s but much prefer 185/45s.
Quote:
On the Carledo, I ran the 5 spoke 6x15 MGF rims (which you don't rate) with 195/50 Toyo Proxes and it was fine, better than fine really, proper point and squirt handling, utterly predictable and great fun. No bump steer, heaviness or lack of response. But the car had been thoroughly lightened and set up for track work and none of the suspension or steering had gone unaltered.

I'd been worried about the car being more than a tad over-tyred having run into the same problem years ago on an old Nova I owned, I tried 6x15 Cav SRI rims with 195/60s and it was AWFUL! Bump steer, massive torque steer, they came off again within the day! None of these issues troubled the Carledo though and the wheel/tyre choice stayed constant for 11 years and 3 sets of tyres. If it ain't broke.......

The jury is still out on the Dolomega with 185/60s on its 14" JBW rims there is a nasty stiffness and heaviness to the steering which is still currently undiagnosed, but i'm pretty sure it isn't down to tyre/wheel choice, i've done something wrong somewhere, probably in the intermediate column area. It may even be a partial seizure in the UJs, they went on early in the buildup of the car and it was several years between fitting and first road test.

I've bought the set of MGF 6 spoke 6x15s to try on the Dolomega with probably 185/60/15s (if the 185/55s on the old MGF front wheels clear the rear arches) If it doesn't work, i'll just move them on again, they weren't expensive.

Steve
Quote:
One of the concerns and/or interests that are commonly expressed about changing tyre sizes, are the variation in overall engine gearing and speedometer calibration.

It appears that your preferred choices of tyre size, are of circa 4•6% to 7•5% smaller external circumference, than the factory-standard 155 SR13 tyres; which is equivalent to a significant increase in final-drive ratio! Using some of your preferred tyre sizes on a Triumph Dolomite 1850, would be roughly equivalent to substituting a 3•89:1 final-drive ratio in place of the original 3•63:1 final-drive ratio, which might have been what you intended!?!

I would be extremely wary of using ultra-low-profile 45-Series tyres on classic cars like the Triumph Toledo & Dolomite, whose suspension was designed to work in series with the vertical “spring-stiffness” & “damping” of 80-Series or 70-Series radial-ply tyres.

What Can Be Considered Low-Profile Tires?

https://www.utires.com/articles/what-ar ... -used-for/

On my 1974 Triumph Toledo 1300 “HL Special”, I wasn’t really planning to use 55-Series or lower aspect-ratio tyres on any size of wheel and I cannot ever imagine substituting a 16 inch or larger diameter wheel.

Although now regarded as 80-Series tyres, traditional standard-profile tyres such as 155 SR13 (now re-designated as 155/80 R13) and 175 SR13 (now re-designated as 175/80 R13) were said in various literature [including a circa-1983 automotive-engineering conference about wheels & tyres and a later Automobile Association’s AA “Drive” magazine article in early-1992 about tyres] to have an aspect ratio of 82% or 83%.

Jim, your choices of tyre sizes, ALL seem to have substantially smaller external-radii than the Triumph Dolomite Sprint’s factory-standard 175/70 SR13 tyre, which itself is smaller than the other Triumph Dolomite’s & Toledo’s factory-standard 155 SR13 tyre. Why would you wish to have tyres of such small external-radii; perhaps to lower the car’s ground clearance and/or increase the effective gearing ratios!?!

https://tiresize.com/gear-ratio-calculator/

Unless you also selected wheels of a different wheel-offset to compensate, these tyres of substantially smaller external-radii, would also have changed your car’s steering-offset (i.e. scrub-radius), which I anticipate would have altered the car’s steering characteristics.

185/50 R14 tyres – predicted external radius = 270•29 mm (17•00 mm smaller than 175/70 R13)

185/45 R15 tyres – predicted external radius = 273•74 mm (13•85 mm smaller than 175/70 R13)

175/55 R14 tyres – predicted external radius = 274•04 mm (13•55 mm smaller than 175/70 R13)

185/60 R13 tyres – predicted external radius = 276•09 mm (11•00 mm smaller than 175/70 R13)

195/45 R15 tyres – predicted external radius = 278•24 mm (9•35 mm smaller than 175/70 R13)

175/65 R13 tyres – predicted external radius = 278•84 mm (8•75 mm smaller than 175/70 R13)


175/70 R13 tyres – predicted external radius = 287•59 mm


155/80 R13 tyres – predicted external radius = 289•09 mm (1•50 mm larger than 175/70 R13)

155/82 R13 tyres – predicted external radius = 292•19 mm (4•60 mm larger than 175/70 R13)

185/55 R15 tyres – predicted external radius = 292•24 mm (4•65 mm larger than 175/70 R13)

155/83 R13 tyres – predicted external radius = 293•74 mm (6•15 mm larger than 175/70 R13)

185/70 R13 tyres – predicted external radius = 294•59 mm (7•00 mm larger than 175/70 R13)

185/60 R15 tyres – predicted external radius = 301•49 mm (13•90 mm larger than 175/70 R13)

175/80 R13 tyres – predicted external radius = 305•09 mm (17•50 mm larger than 175/70 R13)

175/82 R13 tyres – predicted external radius = 308•59 mm (21•00 mm larger than 175/70 R13)

175/83 R13 tyres – predicted external radius = 310•34 mm (22•75 mm larger than 175/70 R13)

195/55 R16 tyres – predicted external radius = 310•44 mm (22•85 mm larger than 175/70 R13)

185/65 R15 tyres – predicted external radius = 310•74 mm (23•15 mm larger than 175/70 R13)

I have never driven a Triumph Toledo or Dolomite on 185/55 R15 tyres, but I have driven my Triumph Toledo extensively on both 175 SR13 and 185/70 R13 tyres, mounted on 5½ x 13 inch alloy wheels. I would not describe the car’s steering response as being “lumpen” (a word I cannot find in my dictionary!) with these wheel & tyre combinations; but instead, light & responsive to steering-wheel input, and giving good ride-comfort on the public highway, for myself and my passengers, which is also an important consideration.

The 195/55 R16 sized tyres you derided, are of very similar external-radius to that of my car’s “original” 175 SR13 tyres and the proposed 185/65 R15 tyres for my substitute 5½ x 15 inch MG 2000 Maestro alloy wheels. Whether the possibly greater weight of either of these wheel & tyre combinations, would noticeably detract from steering response, is presently a matter of conjecture.

_________________
Regards.

Nigel A. Skeet

Independent tutor of mathematics, physics, technology & engineering, for secondary, tertiary, further & higher education.

https://www.linkedin.com/profile/view?id=308177758

Upgraded 1974 Triumph Toledo 1300 (Toledo / Dolomite HL / Sprint hybrid)

Onetime member + magazine editor & technical editor of Volkswagen Type 2 Owners' Club


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PostPosted:Wed Jun 29, 2022 5:09 pm 
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Joined:Tue May 06, 2014 3:38 pm
Posts:446
Location:South Benfleet, Essex
Formula Ford 1600, 95•25 mm PCD, 34 mm Offset, 5½ x 13 inch Steel Racing Wheels

Whilst undertaking a recent Internet search of 95•25 mm PCD wheels, I stumbled upon the following link re Formula Ford 1600, 5½ x 13 inch steel racing-car wheels (based upon the Triumph wheels’ 95•25 mm PCD), with a choice of 9 mm or 34 mm wheel-offset; the latter of which (Part Nos. 095 34 01 or 095 34 03) seems eminently suitable for Triumph Dolomites & Toledos, owing to their 34 mm wheel-offset.

https://formula-ford.co.uk/formula-ford ... phy%20race.

« In the early days road car wheels were used and the almost standard fitment became wheels made by Dunlop. The rules for Formula Ford 1600 require the wheels to be a standard type manufacture, steel wheel with a 13" diameter and 5.5" width. The majority of cars still use a Triumph based 3.75" (95.25mm) PCD, but a few use Ford PCD of 4.25" (108mm) and some a PCD of 101.6mm (4"). Les Weller launched a new wheel in 1983 and instantly this became the wheel to have winning every major Championship and Trophy race. We became involved in the distribution of FF1600 wheels in 2003. »

« We are proud to be selling Wiz Wheels which were designed by Les Weller with our input. We have chosen to supply this wheel due to its superb design, high strength, light weight and accuracy. The wheel centre is made from Swedish high strength Steel and is double welded for extra security, a first for a Formula Ford wheel and this was our own innovation. This means the centre is welded twice to the rim (on the inside and outside). »

« Wiz Wheels are the ultimate steel racing wheel, if you want dependability, strength, accuracy and are serious about winning, these are the wheels to have. We have unrivalled knowledge of Formula Ford and can draw upon our vast experience to advise which wheels fit your car, so always ask and we will be happy to help. »

« How Our Part Numbers Work »

« For example part no: 095 09 01 »

« 095 = 95.25mm PCD »
« 09 = Offset (ET) in mm »
« 01 = Colour Gloss Black »

« PCD's available: 95.25mm, 108mm »
« Offsets available are +3, +9mm, +34mm »
« Colours available: 01 Black, 02 Silver, 03 White »

« Whats Available? What Fits What? »

• « 095 34 01 commonly called Van Diemen wheels, compatible with 544267 and fitted on many mid 1980's to late 1990's Van Diemen's and others, in Gloss Black [Nigel’s note: 095 34 01 indicates: 95•25 mm PCD, 34 mm wheel-offset & gloss-black colour] »

• « 095 34 03 as above but in Gloss White, compatible with 544269 [Nigel’s note: 095 34 03 indicates: 95•25 mm PCD, 34 mm wheel-offset & gloss-white colour] »


• « 095 09 01 commonly called Swift or standard offset, compatible with 544261 and fitted on many classics/historics such as Merlyn's, Crossle's, Royale's, modern era Ray's Van Diemen's, Spectrum's, Swift's etc, in Gloss Black [Nigel’s note: 095 09 01 indicates: 95•25 mm PCD, 9 mm wheel-offset & gloss-black colour] »

• « 095 09 02 as above but in Silver, compatible with 544262 [Nigel’s note: 095 09 02 indicates: 95•25 mm PCD, 9 mm wheel-offset & silver colour] »

• « 095 09 03 as above but in Gloss White, compatible with 544263 [Nigel’s note: 095 09 03 indicates: 95•25 mm PCD, 9 mm wheel-offset & gloss-white colour] »


• « 108 03 01 commonly called Lola wheels and fitted on various Historics with the less common Ford PCD, in Gloss Black, compatible with 544252 [Nigel’s note: 108 03 01 indicates: 108 mm PCD, 3 mm wheel-offset & gloss-black colour] »

• « 108 03 02 as above but in Silver, compatible with 544253 [Nigel’s note: 108 03 02 indicates: 108 mm PCD, 3 mm wheel-offset & silver colour] »



Here’s another reference to Weller-made, Formula Ford 1600, 95•25 mm PCD racing-car wheels, but there is no mention of wheel-offset:

WELLER CURRENT FORMULA FORD 5.5J X 13″ MULTI HOLE RACE WHEEL 95.25 ML (3.75″) PCD

https://ford-parts.org.uk/weller-curren ... -3-75-pcd/

Image


Weller Wheels list for the Triumph Herald, Vitesse, Spitfire & GT6, a 5½ x 13 inch steel wheel, of 4 x 95•25 mm PCD, 63•7 mm centre-bore & 20 mm wheel-offset, but the relatively small 20 mm wheel-offset would make it relatively unsuitable for Triumph Dolomites & Toledos. The list price of £0•01 less than £120•00 each and the large 63•7 mm centre-bore, doesn’t make it particularly appealing either.

Triumph - Vitesse | Spitfire | Herald | GT6 - 13" | £119.99

https://wellerwheels.com/collections/cl ... vitesse-13

Weller Wheels, 56, The Washford Industrial Estate, Heming Rd, Redditch, B98 0EA
Tel. 01527 - 502203
E-mail: enquiry@wellerwheels.com
Website: https://wellerwheels.com

_________________
Regards.

Nigel A. Skeet

Independent tutor of mathematics, physics, technology & engineering, for secondary, tertiary, further & higher education.

https://www.linkedin.com/profile/view?id=308177758

Upgraded 1974 Triumph Toledo 1300 (Toledo / Dolomite HL / Sprint hybrid)

Onetime member + magazine editor & technical editor of Volkswagen Type 2 Owners' Club


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PostPosted:Sat Jul 02, 2022 5:31 pm 
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Joined:Tue May 06, 2014 3:38 pm
Posts:446
Location:South Benfleet, Essex
Quote:
I can't say how Alastair will get on with his 20mm ET 13s. The fact that they ARE 13s may work just enough in his favour to get him out of trouble. I agree that Sprint rims would be a more suitable choice, but he's faced with an extremely limited supply of these as the only Sprints in NZ are (were) personal imports. I dread to think about the cost of shipping even 4 bare rims to NZ! That and Sprint wheels are an even more hackneyed choice than Minilites.
Quote:
Even so, the relatively modest purchase price of five second-hand Dolomite Sprint wheels from Great Britain plus the shipping cost to New Zealand, might not be very different from the significantly greater purchase price of four or five new reproduction “Minilite” style wheels (about £90 each + 15% GST – Goods & Services Tax) from Palmside in Christchurch, South Island, New Zealand plus the shipping costs to Wellington, North Island, New Zealand.

Size: 13 x 5 PCD 4 Rim depth 21 Offset ET20 with caps and nuts in Silver for Triumph | NZ$181•73 excluding GST

https://palmside.co.nz/collections/whee ... ke-4x95-25

I have finally seen some pictures of Alistair Cox’s Revolution “Minilite” style, 8-spoke, 5 x 13 inch alloy wheels (20 mm wheel-offset) & tyres, which look quite attractive on his green-painted, Triumph Toledo 1500, for which he is still waiting for registration by the New Zealand Transport Authority, before he can legally drive the car.

Alistair Cox’s “Minilite” style wheels & tyres

ttps://www.facebook.com/photo/?fbid=1022542364 ... 9846569519

https://www.facebook.com/photo/?fbid=10 ... 0403192134

From what I can read on the tyre sidewalls, these appear to be MAXXIS MA-P3 tyres, which MAXXIS in New Zealand offer in only 175/70 R13 & 185/70 R13 sizes for 13 inch wheels, so I imagine that Alistair has the smaller of the two sizes, which are more appropriate to the relatively narrow 5 x 13 inch wheels.

https://www.maxxistyres.co.nz/products/maxxis-ma-p3/

https://www.maxxistyres.co.nz/search-ty ... Ute+or+4x4

https://www.maxxistyres.co.nz/search-ty ... ce&start=0

https://www.maxxistyres.co.nz/search-ty ... ce&start=0

MAXXIS are a Taiwanese brand (recall that the MAXXIS 185/55 R15 tyre on one of my MG 2000 Maestro wheels was marked “made in PRC” as an abbreviation of the Peoples’ Republic of China), for which there might be a local factory in New Zealand.

I recall many years ago, that the five Goodyear, 195/60 R14 H tyres for my father’s 1986 Ford Sierra XR4x4, were marked “made in New Zealand”, despite there being Goodyear tyre factories closer to Great Britain and my two replacement Firestone S211, 185/70 SR13 tyres for my Triumph Toledo, were marked “made in RSA” (as an abbreviation of the Republic of South Africa), despite my previous complete set of Firestone S211, 185/70 R13 T tyres having been made in France.

On the Facebook “Toledo Triumphs” Group, Alistair recently stated that he purchased the wheels & tyres as an overall package from Palmside, in Christchurch, New Zealand. However, when I investigated their listing of the tyres they offer, it did not include tyres of either the 175/70 R13 or 185/70 R13 sizes and they don’t appear to offer MAXXIS tyres in any size at all.

https://palmside.co.nz/collections/tyres

https://palmside.co.nz/collections/road ... iameter_13

https://palmside.co.nz/collections/rall ... iameter_13

Quote:
Although now regarded as 80-Series tyres, traditional standard-profile tyres such as 155 SR13 (now re-designated as 155/80 R13) and 175 SR13 (now re-designated as 175/80 R13) were said in various literature [including a circa-1983 automotive-engineering conference about wheels & tyres and a later Automobile Association’s AA “Drive” magazine article in early-1992 about tyres] to have an aspect ratio of 82% or 83%.

175/70 R13 tyres – predicted external radius = 287•59 mm

155/80 R13 tyres – predicted external radius = 289•09 mm (1•50 mm larger than 175/70 R13)

155/82 R13 tyres – predicted external radius = 292•19 mm (4•60 mm larger than 175/70 R13)

155/83 R13 tyres – predicted external radius = 293•74 mm (6•15 mm larger than 175/70 R13)

185/70 R13 tyres – predicted external radius = 294•59 mm (7•00 mm larger than 175/70 R13)

175/80 R13 tyres – predicted external radius = 305•09 mm (17•50 mm larger than 175/70 R13)

175/82 R13 tyres – predicted external radius = 308•59 mm (21•00 mm larger than 175/70 R13)

175/83 R13 tyres – predicted external radius = 310•34 mm (22•75 mm larger than 175/70 R13)

So far, I have driven my Triumph Toledo 1300 with several combinations of wheel, tyre and front steering and/or suspension geometry as follows, but it was with the 5½ x 13 inch Cosmic alloy wheels (21 mm wheel-offset) and low-profile, Firestone S211, 185/70 R13 tyres, that without any advanced warning, I experienced the unnervingly rapid transition from under-steer to over-steer when negotiating tight, small-radius bends under power; obliging me to instantly & rapidly reduce the applied steering lock, to avoid hitting the nearside kerb or running off the road onto the verge! The first time it occurred, it was a somewhat frightening experience!

https://low-offset.com/workshop/underst ... oversteer/

A few years later, when I substituted 5½ x 13 inch Triumph Dolomite Sprint alloy wheels (35 mm wheel-offset) and transferred over my existing Firestone S211, 185/70 R13 tyres, the wayward steering characteristics, of rapid transition from under-steer to over-steer, immediately vanished!

Cosmic 5½ x 13 inch alloy wheel – 21 mm wheel-offset | Uniroyal Rallye 180, 175 SR13 radial-ply tyre | factory-standard front-wheel camber => Very civilised, predictable steering characteristics

Cosmic 5½ x 13 inch wheel – 21 mm wheel-offset | Kelly-Springfield Steelmark, 175 SR13 radial-ply tyres | factory-standard front-wheel camber => Very civilised, predictable steering characteristics

Cosmic 5½ x 13 inch wheel – 21 mm wheel-offset | Kelly-Springfield Steelmark, 175 SR13 radia-plyl tyres | all front-wheel camber-adjustment shims removed => Very civilised, predictable steering characteristics

Cosmic 5½ x 13 inch wheel – 21 mm wheel-offset | Firestone S211, 185/70 R13 radial-ply tyres | all front-wheel camber-adjustment shims removed => unnerving transition from under-steer to over-steer when negotiating bends under power

Triumph Dolomite Sprint GKN 13 x 5½ inch wheels – 35 mm wheel-offset | Firestone S211, 185/70 R13 radial-ply tyres | all front-wheel camber-adjustment shims removed => Very civilised, predictable steering characteristics

This later led me to wonder, whether the Cosmic wheels’ lesser offset (21 mm wheel-offset) in combination with the ‘original’ 175 SR13 tyres’ larger external-radius, might have wholly or partially cancelled each other’s effects on steering-offset (aka scrub radius), to retain similar steering characteristics, to what would probably have been the norm, with the original factory-fitted wheels & tyres!?! Having never driven the car, with the original factory-fitted 4 x 13 inch steel wheels (circa 35 mm? wheel-offset) and 155 SR13 tyres, I could only speculate.

175 SR13 tyres have a circa 14•0~15•75 mm larger external-radius than that of 185/70 R13 tyres

175 SR13 tyres have a circa 16•4~16•6 mm larger external-radius than that of 155 SR13 tyres

175 SR13 tyres have a circa 21•0~22•75 mm larger external-radius than that of 175/70 R13 tyres

Noting that Alistair’s 175/70 R13 tyres have an even smaller external radius than my 185/70 R13 tyres, and his 5 x 13 inch “Minilite” style wheels have a 1 mm smaller wheel-offset than my former 5½ x 13 inch Cosmic wheels, I fear he might experience more wayward steering characteristics than I did, owing to a much greater change in steering-offset, so I hope he will be especially careful when he first drives the car on windy roads, because he might suddenly, without warning, have to radically decrease the applied steering lock to avoid hitting the kerb or mounting the verge!

Does anyone by chance, know the factory-standard steering-offset (aka scrub radius) specifications for the Triumph Toledo or Dolomite, with either the factory-fitted 4 x 13 inch steel wheels & 155 SR13 tyres, 4½ x 13 inch steel wheels & 155 SR13 tyres or 5½ x 13 inch alloy wheels & 175/70 SR13 tyres?

https://www.superproeurope.com/technica ... angles.cfm

https://www.superproeurope.com/technica ... es.cfm#sai

https://www.superproeurope.com/technica ... crubradius

https://www.drivingline.com/articles/st ... ub-radius/

https://low-offset.com/workshop/car-sus ... explained/

https://low-offset.com/workshop/positiv ... el-camber/

https://low-offset.com/workshop/underst ... el-offset/

https://low-offset.com/workshop/scrub-radius-explained/

https://low-offset.com/workshop/king-pin-inclination/

The factory-standard specifications for the Triumph Toledo’s king-pin inclination (aka steering axis inclination), are given in Section 57 – Steering, of the official BLMC Triumph Toledo manual as follows, so if one knew the factory-standard steering-offset specifications for a given wheel & tyre combination, it should hopefully be possible to determine the actual steering-offset, for any given combination of wheel-offset and tyre external radius.

Commission No. . . . Kerb Condition . . . Laden Condition (4 up)

Condition ‘A’ . . . . . 6½º ± 1º . . . . . . . . . 7¾º ± ¾º

Condition ‘B’ . . . . . 5¾º ± 1º . . . . . . . . . 6½º ± ¾º

Condition ‘C’ . . . . . 5¾º ± 1º . . . . . . . . . 6½º ± ¾º


Condition ‘A’ – up to Commission Nos. ADG 11512 and ADS 648 only

Condition ‘B’ – from Commission Nos. ADG 11512 and ADS 648 and other models

Condition ‘C’ – from Commission Nos. ADH 1 and ADF 50,001

_________________
Regards.

Nigel A. Skeet

Independent tutor of mathematics, physics, technology & engineering, for secondary, tertiary, further & higher education.

https://www.linkedin.com/profile/view?id=308177758

Upgraded 1974 Triumph Toledo 1300 (Toledo / Dolomite HL / Sprint hybrid)

Onetime member + magazine editor & technical editor of Volkswagen Type 2 Owners' Club


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PostPosted:Tue Jul 05, 2022 4:31 pm 
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Joined:Tue May 06, 2014 3:38 pm
Posts:446
Location:South Benfleet, Essex
Weights of Substitute Wheels & Tyres
Quote:
I've also found a set of F alloys on ebay in a style I quite like (6 blocky, parallel spokes) WITH tyres for £120. The tyres have decent tread but are the usual MGF combo of 2 x 185/55 and 2 x 205/50. But I could TRY the 185/55s on the back and see how it goes, before I spend money on tyres, something I never thought to do on the Carledo in years gone by. Might also be possible to shave a couple of mm off these too.

I'm not terribly worried about the weight of the F rims, it didn't seem to noticeably upset the Carledo, but then again I expected harsh and noisy from that track focused car, so wasn't surprised when I got it! But it didn't have bump steer or any of the other nasty side effects of too high an unsprung weight.
Quote:
So far, I have yet to weigh my sets of five bare, tyreless 6 x 15 inch MG 2000 Montego & 5½ x 15 inch MG 2000 Maestro cross-lattice style wheels, but for the purposes of initial comparison, of combined wheel & tyre weights, I did weigh the following on my decades old, “less-than-accurate” Vanguard bathroom scales.

Dolomite Sprint 5½J x 13 inch wheels & Firestone S211, 185/70 R13 (circa 6 mm tread): weight = 2 st 0 lbs = 28 lbs = 12•7 kg

MG Maestro 5½J x 15 inch wheel & Michelin MXV2, 185/55 R15 tyre (circa 2½ mm tread): weight = 2 st 2 lbs = 30 lbs = 13•6 kg

MG Maestro 5½J x 15 inch wheel & Cheng Shin Maxxis, 185/55 R15 tyre (circa 6~7 mm tread): weight = 2 st 6 lbs = 34 lbs = 15•4 kg

It’s interesting to note the apparent 1•8 kg weight difference, between the nearly four-fifths worn MXV2 tyre and the nearly new Maxxis tyre. If one were to substitute either 185/60 R15 or 185/65 R15 tyres, then one would expect the wheel & tyre combinations to be somewhat heavier, owing to the increased quantity of textile-reinforced rubber. Compared to the weight of the heavy, rear live-axle, this increase would be relatively insignificant, but it remains to be seen what effect this will have on the front suspension.

I finally got around to weighing the bare, tyreless 6 x 15 inch MG 2000 Montego & 5½ x 15 inch MG 2000 Maestro cross-lattice style wheels on the same Vanguard bathroom scales that I used to weigh the 5½ x 13 inch Dolomite Sprint wheel with tyre and the two 5½ x 15 inch MG 2000 Maestro wheels with tyres. I got different values of weight measurements, using two other bathroom scales (one reading was fairly-close, to within a ½ lb, and the other was way off!) that I managed to borrow, so I cannot assume that any of these values are accurate, but having been weighed on the same Vanguard bathroom scales, they do form a basis for comparison.

MG Maestro 5½J x 15 inch wheel with no tyre: weight = 1 st 1½ lbs = 15½ lbs = 7•0 kg

MG Montego, 6J x 15 inch wheel with no tyre: weight = 1 st 3 lbs = 17 lbs = 7•7 kg

Using the weight of the tyreless MG Maestro 5½J x 15 inch wheel, one can estimate the weights of the Michelin & Maxxis 185/55 R15 tyres as follows:

Michelin MXV2, 185/55 R15 tyre (circa 2½ mm tread): weight = 13•6 kg – 7•0 kg = 6•6 kg

Cheng Shin Maxxis, 185/55 R15 tyre (circa 6~7 mm tread): weight = 15•4 kg – 7•0 kg = 8•4 kg

Unless I can persuade the local post office to let me use their parcel scales, that’s the best I can do for the moment! If I had still been working at Celcon’s R & D laboratory (mid-1984 to early-1988), I could have used the large scale 1•5 m x 1•5 m, digital platform balance, on which I used to weigh 2 m x 2 m masonry wall samples in RSJ (i.e. rolled steel joist) frames, of up to 2 tonnes, to a precision of ± 0•01 kg.

If at some time in the future, Steve Boitoult weighs his 6 x 15 inch MG-F 6-spoke alloy wheels with Ling Long 185/55 R15 tyre & Toyo Proxes 185/60 R15 tyre, we shall have a further basis for weight comparison. I would expect a new 185/60 R15 tyre to be heavier on average than a new 185/55 R15 tyre, but it would be interesting to know by how much; bearing in mind that the Ling Long tyres are part-worn. I envisage that the weight-difference between a new 185/65 R15 and a new185/55 R15 tyre, would be slightly more than twice the weight-difference between a 185/60 R15 and 185/55 R15 tyre, owing to the additional 5% of 185 mm increase in sidewall height and the slightly larger tyre-tread circumference.

Browsing through some of the archived files on my computer, pertaining to wheels & tyres, I discovered a file downloaded from the Internet on 7th November 2016, entitled “CEC TYRE DATABASE 195 MEANS”, which lists in ascending order of mean tyre-weight, 76 different tyre brands & models, of size 195/65 R15 (i.e. the next size up from 185/65 R15); the lightest of which was said to be 9•27 lbs (i.e. 4•206 kg) and the heaviest was 12•44 lbs (i.e. 5•644 kg), of which the heaviest is 34•2% more than the lightest. It also listed details of UTQG Temperature, UTQG Traction, UTQG Treadwear & speed ratings.

https://en.wikipedia.org/wiki/Uniform_T ... ty_Grading

https://en.wikipedia.org/wiki/Uniform_T ... #Treadwear

https://en.wikipedia.org/wiki/Uniform_T ... g#Traction

https://en.wikipedia.org/wiki/Uniform_T ... emperature

https://www.prioritytire.com/blog/tire- ... ting-utqg/

barrystiretech.com/rrandfe2.html

https://www.energy.ca.gov/transportatio ... 0MEANS.doc

According to the information given in the following Oponeo wheel & tyre supplier’s blog, typical weights of 185/70 R13 tyres are circa 7•0~7•2 kg; implying that the Dolomite Sprint wheels weigh circa 5•5~5•7 kg (i.e. 12•7 kg – 7•0~7•2 kg), or maybe a little less, given that the aforementioned Firestone S211, 185/70 R13 tyre was part-worn.

https://www.oponeo.co.uk/blog/how-much- ... tyre-weigh

« 185/70 R13 between 7•0 and 7•2 kg »
« 175/65 R14 between 6•5 and 7•2 kg »
« 195/65 R15 between 8•2 and 9 kg »


The 8•2~9 kg weight range for the 195/65 R15 size tyres, cited in the Oponeo wheel & tyre supplier’s blog, differs markedly from the circa 4•2~5•6 kg, range that is cited in the “CEC TYRE DATABASE 195 MEANS” document. This leaves one wondering what to believe!?!

Out of idle curiosity, I also decided to weigh some of the other wheel & tyre combinations that I have, associated with my 1973 VW Type 2 motor-caravan upgrade projects, which include the following:

Set of six factory-standard, 1971~79 VW Type 2, 5½ x 14 inch steel-wheels (5 x 112 mm PCD | 39 mm wheel-offset | circa 66•6 mm scalloped non-circular centre-bore) & 185 SR14 Reinforced tyres [325•8 mm predicted external radius].

Set of four (I need another two spares) 2002/03 Mercedes C-Class 7 x 16 inch alloy-wheels (5 x 112 mm PCD | 37 mm wheel-offset | 66•6 mm centre-bore) with the “original” 205/55 R16 tyres [315•9 mm predicted external radius]

Pair of Vauxhall Movano and/or Renault Master, ? x 16 inch steel-wheels (5 x 130 mm PCD by measurement & calculation| 66½ ± ½ mm wheel-offset by measurement & calculation| | 89 mm centre-bore by measurement) with 215/65 R16C commercial-van tyres [342•9 mm predicted external radius] of different brands.

Their weights, determined using the same Vanguard bathroom scales, as was used for the MG 2000 Maestro & MG 2000 Montego wheels & tyres are as follows:

VW Type 2, 5½ x 14 inch steel-wheel & Michelin XZX, 185 SR14 Reinforced (95½ load-index = maximum load of 1540 lbs or 698•7 kg @ 40 psi | circa 7 mm tread-depth): weight = 2 st 12½ lbs = 40½ lbs = 18•4 kg

Mercedes C-Class, 7 x 16 inch alloy-wheel & Continental Premium Contact 2, 205/55 R16, 91V @ 51 psi (circa 3 mm tread-depth): weight = 2 st 8 lbs = 36 lbs = 16•3 kg

Vauxhall Movano, ? x 16 inch (thought to be 6 x 16 inch) steel-wheel & Continental Vanco-6, 215/65 R16C, 106/104T @ 55 psi (circa 3~4 mm tread-depth): weight = 3 st 9½ lbs = 51½ lbs = 23•4 kg

Vauxhall Movano, ? x 16 inch (thought to be 6 x 16 inch) steel-wheel & Michelin Agilis 81, 215/65 R16C, 109/107R @ 69 psi (circa 3~4 mm tread-depth): weight = 3 st 12½ lbs = 54½ lbs = 24•7 kg [slightly less than a half-hundredweight]

A weight difference of more than 7 kg between a 16 inch alloy-wheel & 205/55 R16 tyre and a 16 inch steel-wheel & 215/65 R16C tyre is considerable, but I wonder how much of this is accounted for by the weight differences between the 16 inch steel and alloy wheels!?!

If I manage to successfully employ the off-road, overland expedition technique, for removing & fitting tyres, using a lifting-jack & tyre-levers, I shall find out in due course! I shudder to think how much an HGV lorry wheel & tyre would weigh; probably heavier than I could lift!

I salvaged the two discarded Vauxhall Movano and/or Renault Master, 16 inch steel-wheels & 215/65 R16C commercial-van tyres, which I found locally in a waste-skip (at a closed, privately-run, high-dependency medical unit, where I also found a few high-visibility waistcoats, two full-length ambulance-stretcher mattresses and a lot of carpet tiles), with a view to trial-fitting the ZERO-COST tyres on the 7 x 16 inch Mercedes C-Class alloy wheels, so that I can check whether there might be any interference problems, when fitted to the 1973 VW Type 2 motor-caravan. If they’re okay, I can keep them both as my emergency spares.

https://www.wheel-size.com/size/vauxhall/movano/

https://www.wheel-size.com/size/renault/master/

Various model-years & models, of Vauxhall Movano & Renault Master vans, appear to have been equipped with 6J x 16 inch steel wheels (130 mm PCD | 89•1 mm centre-bore | 66 mm wheel-offset), fitted with either 215/65 R16C or 225/65 R16C tyres; both of which seemed rather wide for a 6 inch wide wheel, but according to the information at the following link, 6 inches & 6½ inches are the minimum & standard wheel-rim-widths for both tyre sizes. Also given, are recommended wheel sizes for 205/55 R16 tyres, as fitted to the 2002/03 Mercedes C-Class saloon’s 7 x 16 inch alloy wheels.

http://www.tyresizecalculator.com/tyre- ... calculator

Tyres: 205/55 R16 => Wheels: 16 x 5½ minimum | 16 x 6½ standard | 16 x 7½ maximum

Tyres: 215/65 R16 => Wheels: 16 x 6 minimum | 16 x 6½ standard | 16 x 7½ maximum

Tyres: 225/65 R16 => Wheels: 16 x 6 minimum | 16 x 6½ standard | 16 x 8 maximum

Recommended wheel sizes for 185/80 R14 tyres (C or Reinforced), that were the factory-standard radial-ply tyre option for the 1973 VW Type 2 are also given; 7.00 x 14 8PR cross-ply tyres being the norm for all models, except the fire-truck and deluxe microbus! The 1971~79 VW Type 2s were factory-fitted with 5½ J x 14 inch steel wheels, whose size is midway between the standard & maximum wheel-rim widths.

http://www.tyresizecalculator.com/tyre- ... calculator

Tyres: 185/80 R14 => Wheels: 14 x 4½ minimum | 14 x 5 standard | 14 x 6 maximum

_________________
Regards.

Nigel A. Skeet

Independent tutor of mathematics, physics, technology & engineering, for secondary, tertiary, further & higher education.

https://www.linkedin.com/profile/view?id=308177758

Upgraded 1974 Triumph Toledo 1300 (Toledo / Dolomite HL / Sprint hybrid)

Onetime member + magazine editor & technical editor of Volkswagen Type 2 Owners' Club


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PostPosted:Mon Jul 11, 2022 5:25 pm 
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Future Club member hopefully!
Future Club member hopefully!

Joined:Tue May 06, 2014 3:38 pm
Posts:446
Location:South Benfleet, Essex
Quote:
For my own interest, I examined the available wheels of 13 inches and greater diameter (i.e. 13, 14 & 15 inches diameter), with a 4 x 3¾ inches (i.e. 4 x 95•25 mm) PCD – pitch circle diameter that are listed on John Brown Wheels’ Internet website. Not one of the wheels listed there could be considered particularly suitable for Triumph Dolomites & Toledos, and some might be considered grossly if not dangerously unsuitable!

John Brown Wheels, Unit 1, Cornwood Farm, Napton Road, Stockton, Warwickshire, CV47 8HU
Tel. +44 (0) 1926 817 444
E-mail: sales@johnbrownwheels.com
Website: https://www.johnbrownwheels.com

I am aware that the 5½ x 13 inch Dolomite Sprint alloy wheels have a 35 mm wheel-offset and a circa 56~57 mm centre-bore diameter. My substitute 5½ x 15 inch MG 2000 Maestro alloy wheels have a slightly smaller 31 mm wheel-offset and a circa 56~57 mm centre-bore diameter; which to date is the closest match and most suitable substitute wheel, that I have so far managed to identify.

In contrast, 25 mm is the largest wheel-offset of any of the John Brown Wheels with a 4 x 3¾ inches (i.e. 4 x 95•25 mm) PCD – pitch circle diameter and all the alloy wheels are said to have a 67•1 mm, centre-bore diameter which would require the use of a spigot ring (aka hub-centric ring) of some description. I would feel rather uncomfortable relying solely on just four x four relatively puny 3/8” UNF wheel-fixing studs to support the weight of a fully-laden Triumph Toledo (circa 1¼ tonnes) or Triumph Dolomite on their own.

https://www.performancealloys.com/acces ... igot-rings

https://www.oponeo.co.uk/blog/hub-diame ... igot-rings

Strangely, the “Smoothie” steel wheel, is said to have a 157 mm centre-bore diameter, which seems inordinately large! Given that it would be impossible to have a 157 mm centre-bore diameter exceeding the 95•25 mm PCD, this must be a mistake! I wonder whether the centre-bore diameter is actually 57 mm!?!

https://www.johnbrownwheels.com/wheels/

13 Inch Diameter Steel & Alloy Wheels

5½ x 13 inch – “Smoothie” steel | 20 mm offset | 157 mm !?! centre-bore | 7•00 kg weight | £82•45 unit price

https://www.johnbrownwheels.com/product ... 5513SMO495

On Sunday, 19th June 2022, I sent an e-mail to John Brown Wheels, drawing their attention to the anomaly regarding the stated 157 mm centre-bore diameter exceeding the 95•25 mm PCD, of their 13 inch “smoothie” steel wheels. I also suggested that they draw attention to the probable need to use spigot rings in conjunction with their various wheels of large 67•1 mm centre-bore and 95•25 mm PCD, for Triumphs and other cars which utilise the 95•25 mm PCD and require wheels of significantly smaller, 56~57 mm centre-bore, as well as cautioning against substituting wheels of inappropriate wheel-offset.

I have so far yet to receive any reply, but when I checked the John Brown Wheels’ website on Saturday, 9th July 2022, they had amended the specification details of their 13 inch “smoothie” steel wheels, but do not appear to have done anything else!

5½ x 13 inch – “Smoothie” steel | 20 mm offset | 67•1mm centre-bore | 7•00 kg weight | £82•45 unit price

https://www.johnbrownwheels.com/product ... 5513SMO495

_________________
Regards.

Nigel A. Skeet

Independent tutor of mathematics, physics, technology & engineering, for secondary, tertiary, further & higher education.

https://www.linkedin.com/profile/view?id=308177758

Upgraded 1974 Triumph Toledo 1300 (Toledo / Dolomite HL / Sprint hybrid)

Onetime member + magazine editor & technical editor of Volkswagen Type 2 Owners' Club


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