wheel upgrade

[Ron L]

Hi
Can anyone here save me some time and hassle. Got a 350i mk1 that is on the standard 7j x 15" lattice wheels. Want to upgrade to 17" but would also like to widen them to 7.5 or 8J. Has anyone done a similar mod, and what ET was used (currently mine are 23, but to retain the same limits wheel choice) and did everything clear ok?
Any help would be greatly appreciated

[FrenchTVR]

Hi,

I have 7j x 17 Borbets on my 350i. I run 215/45x17 Tyres with no fouling problems. Can't remember the offset, will have a look later.

Photos on my profile and website.

Mick

[DevonIain]

I've looked at having different wheels on my 350i several times, but have always been warned off because they are very rare with the correct offset. Does the offset affect the handling or could I get away with a 'modern' set of fwd wheels and use spacers to make up the difference?

Excuse me not being very technical.

[19560]

DevonIain said:

I've looked at having different wheels on my 350i several times, but have always been warned off because they are very rare with the correct offset. Does the offset affect the handling or could I get away with a 'modern' set of fwd wheels and use spacers to make up the difference?

Hi there. The standard offset for a 350i is 23 and for FWD current cars it's 70. The 350i is fairly forgiving for offsets (+/- about 10 or 12mm) but not to that extent. Some Mercedes wheels have the same stud spacing and are close on offsets.

FrenchTVR said:

I have 7j x 17 Borbets on my 350i. I run 215/45x17 Tyres with no fouling problems.

IMHO that's the best choice for tyres although I'd go for 7.5j with a 20mm offset.
You could also try 16" with 205/55 or 50 all round or 225/45 at the rear.

[gsx600]

I use 17 cup raider alloys on the 350. They came off an old 3.0 Turbo Supra I had.

Fit is really good and even 225's just fitted, now on 205 to make turning easier

I;ll try and send you a pic if interested / measure offset etc

Also tried 17 Vecta GSI wheels which fitted as well but only as a temp measure, not tried the MV6 wheels yet but looks like they would fit as well

[19560]

gsx600 said:

Fit is really good and even 225's just fitted, now on 205 to make turning easier

Remember that that is for a 400SE whereas IMHO you may struggle with 225 in the front of a 350 (and the rear with A frame)


There are a few other points; assuming that you keep the rolling radius the same then larger wheels will:

Downside: - cost more, have more expensive tyres, perform worse in the wet, perform worse on bumpy roads, be more susceptible to tram lining, increase the weight of the car, increase the unsprung weight, produce a harsher ride, increase the rotating unsprung weight (second moment of inertia) and be more liable to scuffing on kerbs when parking.

On the plus side they should: - prevent the tyre from distorting thus giving greater cornering grip in the dry and on smooth roads, be more direct giving greater steering feel, produce less heat and be better for long high speed journeys, have less tyre wall flex (thus reducing both heat and fatigue) and effectively increase the spring rates being an easy way to fine tune your springing rates from summer to winter if you swap back to the smaller wheels for winter and they should look good.

Also note that fitting lower section tyres with less sidewall flex can make the car more sensitive to suspension geometry changes. Lowering the car can adversely affect the handling by throwing the static geometry out, and giving you too much camber correction and bump steer.

[bhardy]

I've got 17inch borbets (same as frenchtvr) with 205/..(can't remember, have to take a look) and they give the 350i great handeling! The ride becomes a bit hard which i don't mind. The borbets look very good on the 350i (IMHO) and the only - is that when driving with a passenger over long dents in the road they hit the wheelarch. But if you want to look perfect you will have to suffer a bit........

>> Edited by bhardy on Tuesday 4th January 14:18

[19560]

bhardy said:

I've got 17inch borbets (same as frenchtvr.) The ride becomes a bit hard which i don't mind. The borbets look very good on the 350i (IMHO) and the only - is that when driving with a passenger over long dents in the road they hit the wheelarch. But.....you will have to suffer a bit........

They shouldn't hit the wheel arch though. The rolling dia is very similar so the only downside to cause hitting the arches seems to be the weight of the wheels. Dare I say it but maybe some stiffer springs? What rate do you currently have on?

[bhardy]

19560 said:

bhardy said: I've got 17inch borbets (same as frenchtvr.) The ride becomes a bit hard which i don't mind. The borbets look very good on the 350i (IMHO) and the only - is that when driving with a passenger over long dents in the road they hit the wheelarch. But.....you will have to suffer a bit........ They shouldn't hit the wheel arch though. The rolling dia is very similar so the only downside to cause hitting the arches seems to be the weight of the wheels. Dare I say it but maybe some stiffer springs? What rate do you currently have on?

Haven't got a clue which rate i have, all i know is that it's pretty stiff and the dia seems bigger cause it really fills the whole arch (look at my profile) and it is not that big a problem as it only happens when fully packed on vacation or when going to fast over large dented sectoins of road where you should have slowed down in te first place. At the circuit however, the tires hit the front arch when cornering really hard so i'm thinking of putting stiffer ones in front!!

[bhardy]

19560 said:

bhardy said: I've got 17inch borbets (same as frenchtvr.) The ride becomes a bit hard which i don't mind. The borbets look very good on the 350i (IMHO) and the only - is that when driving with a passenger over long dents in the road they hit the wheelarch. But.....you will have to suffer a bit........ They shouldn't hit the wheel arch though. The rolling dia is very similar so the only downside to cause hitting the arches seems to be the weight of the wheels. Dare I say it but maybe some stiffer springs? What rate do you currently have on?

Haven't got a clue which rate i have, all i know is that it's pretty stiff and the dia seems bigger cause it really fills the whole arch (look at my profile) and it is not that big a problem as it only happens when fully packed on vacation or when going to fast over large dented sectoins of road where you should have slowed down in te first place. At the circuit however, the tires hit the front arch when cornering really hard so i'm thinking of putting stiffer ones in front!!

[19560]

bhardy said:

(Look at my profile.) At the circuit however, the tires hit the front arch when cornering really hard so i'm thinking of putting stiffer ones in front!!

The 215/45/17 is spot on for dia.. I think that you may have 205/50/17s which are 1.5% oversized although that shouldn't be a problem, even for trackdays. I can only imagine that you have lowered or sagging springs. I would consider fitting springs an inch longer in compressed length, even if you fit stiffer ones. Or if you have adjustable spring seats then it's even easier.

[FrenchTVR]

bhardy said:

and the only - is that when driving with a passenger over long dents in the road they hit the wheelarch.

Mine had done this when I first purchased the car. It was caused by the front springs and shocks being knackered. Have never had any contact problems since fitting new ones from RT racing.

Handling is very good wet and dry, but I have to confess to not having enough experience of Wedges on the standard set-up.

[bhardy]

i've fitted new koni's in front last year but i think the front springs may not be that good! Would be a nice job for the winter. The rear springs i believe are very stiff and in good condition.

I've had a look and they are 205/50/17. It's not a real problem but i'm thinking about the front spring and may fit 215/45/17 next time i need tires. Got bridgestone s02's and they wear quite fast....

[campbell]

I have a set of 16'' from a Cerbra on the SEAC and all ive had to do is put s set of 5mm wheel spacers on the back to make sure the tyre wont fowl the rear tralling arm, the tyres are 245,45 16'' all round.
I wanting a set of 17'' from a Cerbra next, i think the off set will be better than the 16'' with the same width of tyre.
Campbell

[hansdaal]

Hallo,

Is the PCD the same ???
I.M.H.O. the Seac PCD is 5/112 and the Cerbera is 5/114,3 but I'am not complete sure.
Did the wheels fit straight on.??

Greetings

Hans

[19560]

hansdaal said:

Is the PCD the same ??? I.M.H.O. the Seac PCD is 5/112 and the Cerbera is 5/114,3 but I'am not complete sure. Did the wheels fit straight on.??

The tolerance must be enough to allow for the PCD difference so that the wheels just fit over the studs however the nuts won't be concentric with the wheel and so some very odd stress patterns will occur. I wouldn't do it.
Have a look at www.pistonheads.com/gassing/topic.asp?t=127166&f=12&h=0&hw=pcd+wedge+cerbera

[campbell]

well i have fitted the 16'' cerbera wheels onto the SEAC with no problems, all the studs line up in the middle of the holes, if the wheels felt funny when i fitted them i would be funning them and also they fit the Toyota Picknic people carrier too, and make the car look well smart over the standard set up.
Ill get my coat.

If you wanted to be sure you could be to your local TVR garrage and ask for a loan of a wheel and try it on the car at a tyre garrage and ask for there opinion.

Campbell

[redwedge5]

campbell said:

well i have fitted the 16'' cerbera wheels onto the SEAC Campbell

Any pictures available of your car with them fitted? I was intereseted to see what a SEAC looked like with them on....I could be tempted

Great profile site

[campbell]

redwedge5 said:

campbell said: well i have fitted the 16'' cerbera wheels onto the SEAC Campbell Any pictures available of your car with them fitted? I was intereseted to see what a SEAC looked like with them on....I could be tempted Great profile site

Ill sort out some pics for you Redwedge5

Campbell