Wider Wheels for the S1

Dave K · Post by **Dave K** » Wed Jul 20, 2011 8:11 am

Heuer wrote:My car is currently with CMC for service work and they found all four MWS 6" competition SS wheels to have loose spokes - indeed almost every outer spoke! The wheels are eight years old, have done 18,000 miles and will have to go back to MWS to have them reset.

Worth checking the spokes regularly as it is easy to tighten up the odd one but once they all start to come undone it is a factory re-furbishment job.

David

David,

When I was going to buy my new wheels from a well known Jag parts supplier in the UK they told me they stopped selling MWS spoked because of too many warranty issues and now only sold Dayton which is what I bought.

I know plenty of E-Type owners who fit 225 tyres to the rear and 205 at the front which is what I intend to do when I change my tyres shortly. 225 rub at front so it's best to go smaller.
I don't drive it enough unfortunately to worry about the slight handling problems I just want it to look good and will sacrifice handling for looks.

Dave

kingzetts · Post by **kingzetts** » Sat Jul 30, 2011 4:16 pm

I have what is probably a dumb question;

It seems to be generally agreed that to fit wider tyres than 185 it is necessary to cut down/remove the rubber bump stops. But I've never seen the details of this spelled out, in particular;

a) Is it necessary to cut the bump stops with 185 tyres on 6" wheels?
b) Is it necessary to reduce the width of the metal ledge on the bodyshell to which the rubber stop is bolted, or just remove/slice in half the rubber stop itself?
c) Is it possible to play with the offset of the wire wheel (presumably they are made in dirrerent offsets to suit different cars) to ensure the extra width is taken at the outer edge, not the inner edge?

Any experiences/views?

Post by **Heuer** » Sat Jul 30, 2011 5:46 pm

You can fit 185 tyres on 5.5" rear rims without cutting anything away (Jaguar recommended this combination for "competition work"). Never tried it with 185 and 6" but I imagine you will need to either cut the bump stops in half laterally or cut them off altogether. You will most certainly need to remove them entirely if you go to 205/70 tyres on 6" wheels. This naturally causes another problem as you no longer have bump stops so the shock absorbers could fully compress metal to metal which will be both uncomfortable and possibly damaging. The solution is to put bump stops on the shock struts - basically split rubber bungs - but I imagine many cars are running without them because dealers think it is simpler to hack off the bump stops and fit the jumbo wheels/tyres rather than spend time doing the job properly. That said 185 tyres on 6" rims will stiffen handling up a bit with only a small loss in ride compliance so actually a good combination.

As for offsets this was the problem Peder discovered when he bought 6" Borrani wheels. Although those wheels are described as fitting the E-Type in the catalogue it seems the offsets are wrong although they may fit the S3 cars. I spoke to Longstone and they confirmed as much but also agreed the offsets for the S3 cars are the same as the S1/2 cars, just the former has flared wheel arches designed to ensure there is sufficient clearance for the standard 6" rims and 205/70 tyre combination. The problem is not confined to the rear as some people report tyres rubbing against body work at full lock on S1/2's. The solution appears to be to put stops on the steering rack to limit travel. All this is fine for a race car but it totally pointless for an E-Type on the road.

My car produces 286bhp and 350lb/ft and I drive it very hard indeed yet I have never been able to overcome the rear wheel grip during acceleration. In corners my body starts to slide on the seat well before the car does and when the back end breaks away it is in a beautifully controlled fashion. However I drove a friend's E-Type recently and it was fitted with 6" wires and Michelin XWX tyres and it performed much as my own - there certainly was no improvement in road holding but it did lose some delicacy in steering feel and low speed manoeuvring was a challenge.

So in answer to your questions:

a) probably
b) yes for 6", slice rubber for 5.5" to be safe
c) sounds an expensive experiment

Post by **Heuer** » Sat Jul 30, 2011 5:49 pm

Dave K wrote:........... I just want it to look good and will sacrifice handling for looks.

Argh! You are the spawn of the devil

Get thee behind me Satan.

PeterCrespin · Post by **PeterCrespin** » Sat Jul 30, 2011 7:14 pm

Heuer wrote: You can fit 185 tyres on 5.5" rear rims without cutting anything away (Jaguar recommended this combination for "competition work"). Never tried it with 185 and 6" but I imagine you will need to either cut the bump stops in half laterally or cut them off altogether. You will most certainly need to remove them entirely if you go to 205/70 tyres on 6" wheels.

Umm, not nececellery Guvnor. I'm running 205/70 on 6" Daytons with both stops virgo intacto and significant inner clearance on a totally original shell. They are centre-laced, outer clearance is borderline and I had to relieve the wheelarch return somewhat on the right side. That side is a bear to get the wheel off as you can imagine, but I rationalise it by remembering that I'd only change it on a trip if the tyre was flat, which would be easier. They were on Paul Kennedy's S1 before my car and he got a second set the same so presumably he was happy as well? Don't know.

Pete

Post by **Heuer** » Sat Jul 30, 2011 8:11 pm

PeterCrespin wrote: That side is a bear to get the wheel off as you can imagine, but I rationalise it by remembering that I'd only change it on a trip if the tyre was flat, which would be easier.
Pete

Yes but the spare would (hopefully) not be flat! Try getting a fully inflated one fitted with traffic flying past.

Wonder if there is a difference between centre laced and normal wheels? I once had 6" MWS with 225/65 and the bump stops had to be removed. Thing is what happens when the IRS is at its limits under aggressive cornering? Easy to say it is clear when the car is stationery.

kingzetts · Post by **kingzetts** » Sat Jul 30, 2011 9:18 pm

Thanks for the comments, guys.

Just to be absolutely clear, lets define the bump stops as being the rubber stops which bolt onto the bodyshell, and the metal shelf on the bodyshell to which they bolt as the bump stop mounts.

When you talk about cutting or removing the bump stops, do you mean cutting/removing the metal mounts, or just the rubber stops themselves? Obviously the latter is a much less extreme step than the former.

daverawle · Post by **daverawle** » Sat Jul 30, 2011 9:52 pm

I think the repro parts aspect rears its ugly head again. There are bump stops and 'bump stops'. My original ones, well they came with the car, are canted around 20 degrees to the outside. Reversing them means they don't come close to the tyres, which are 205x70. I've seen repro bump stops which are straight and very wrong. Remove them? No way, Jaguar didn't fit them for no reason and mine polish a patch on the hub carriers so they are serving a purpose.

Edited: These are 6" Daytons

Dave

kingzetts · Post by **kingzetts** » Sun Jul 31, 2011 11:41 am

I should say that if I did "remove" them I would fit bump stops on the shocks, as described by David.

christopher storey · Post by **christopher storey** » Sun Jul 31, 2011 5:54 pm

My FHC has 6" wheels , now with 185s. There is still a suspicion that the tyres are connecting with the bump stops at a significant downward deflection of the body over an undulation, because I have been plagued with an intermittent very slight vibration which only I can feel through the pedals when the rear of the car dips - passengers cannot detect it - and there are no significant witness marks on the tyres . Nonetheless, since it only happens with a tank more than 1/2 full, I suspect that there is contact of a minimal nature . It does not seem to happen with my other set of 5.5 wheels, and I think the conclusion must be that with 6" wheels some trimming of the stops AND their metal connection is necessary

kingzetts · Post by **kingzetts** » Sun Jul 31, 2011 6:32 pm

Christopher,
I'm confused. I thought that the contact between tyres and bump stops was likely to take place when the suspension was at full drop or approaching it. Surely when the suspension is near full compression, with the bump stops near to or touching the axle carrier, then the bump stops are inside the "well" of the wheel/tyre?

pmansson · Post by **pmansson** » Sun Jul 31, 2011 6:32 pm

Don?t want to interfere, but with my recent issues with 6" Borranis not fitting inside the wheel arches, it strikes me that offset is the culprit in many instances.
The Borranis were so off centre in the wheel arches between the bump stops and the inside of the fender/rear wing, that you could fit a closed fist between the tyre and the bump stops.
I aslo want to mention that Longstone have handled this mishap very professionally indeed, and they and the Italians have learned a lesson and Borrani?s website will be changed as far as options for the E are concerned.

PeterCrespin · Post by **PeterCrespin** » Sun Jul 31, 2011 10:29 pm

kingzetts wrote:Christopher,
I'm confused. I thought that the contact between tyres and bump stops was likely to take place when the suspension was at full drop or approaching it. Surely when the suspension is near full compression, with the bump stops near to or touching the axle carrier, then the bump stops are inside the "well" of the wheel/tyre?

You're right John. At full compression it is the outer sidewall rubbing that's the issue at the tyre/wheelarch interface. Bump stops are only an issue at, or near to, full extension.

As for witness marks, if they aren't clear then grab a handful of soil and rub it all around the tyre sides to make them uniformly dusty or muddy brown. ANY rubbing will very quickly show up as clear black arcs or full circles on the brownish background. If none appear, there is no rubbing, unless it's at the top of the arch by the tread section, which I don't think is possible with normal-sized parts or modest oversizes.

I'd guess a minor vibration at full bump might be a UJ issue (prop or half shafts) or maybe some kind of loose hanbrake cable rubbing or radius arm tension thing?
Pete

christopher storey · Post by **christopher storey** » Mon Aug 01, 2011 4:40 am

It is hard to tell exactly when my vibration appears/disappears over undulations, but it is noticeable that with a full tank I can reproduce it on hard acceleration when there is a degree of squat, which suggests that it is on bump rather than rebound that something is touching. I do not think it is a driveshaft UJ problem as it does not occur with my other set of wheels and in any event does not produce the characteristic blurred mirror of transmission vibrations. Curiouser and curiouser

PeterCrespin · Post by **PeterCrespin** » Mon Aug 01, 2011 9:03 am

christopher storey wrote:It is hard to tell exactly when my vibration appears/disappears over undulations, but it is noticeable that with a full tank I can reproduce it on hard acceleration when there is a degree of squat, which suggests that it is on bump rather than rebound that something is touching. I do not think it is a driveshaft UJ problem as it does not occur with my other set of wheels and in any event does not produce the characteristic blurred mirror of transmission vibrations. Curiouser and curiouser

Hmm, odd. If it is directly linked to a given set of wheels, then either it is wheel-related in terms of some loose spokes or off-balance or something (unlikely?) or there is indeed some kind of fouling.

It's a bit messy rubbing soil over the tyre sidewalls but not too bad in dry weather. Once you have done it then you can instantly confirm/exclude any rubbing issues, as the results are so visible. I would also look inside the wheelarch for rubbing marks on the bodywork above and to the inner side perhaps, since it's harder to spot rubbing by the tread surface as the sidewall dust/mud trick obviously doesn't work.

In your shoes (boots) that would definitely be my next step and if no rubbing exists, you can focus elsewhere.

Pete

Post by **Heuer** » Mon Aug 01, 2011 9:36 am

PeterCrespin wrote: Hmm, odd. If it is directly linked to a given set of wheels, then either it is wheel-related in terms of some loose spokes or off-balance or something (unlikely?) or there is indeed some kind of fouling.
Pete

Not really a surprise, MWS wheels seem to lose spoke tension very quickly. Mine had to go back to the factory for resetting as so many were loose after 15,000 miles.

Rubbing soil on the tyres is an interesting alternative to the industry standard use of talc for testing of gaps, leaks and contact though

christopher storey · Post by **christopher storey** » Mon Aug 01, 2011 12:00 pm

I shall have a go at the soil marking in due course and report back. Thank you all for the suggestions

PeterCrespin · Post by **PeterCrespin** » Mon Aug 01, 2011 4:05 pm

Heuer wrote: Rubbing soil on the tyres is an interesting alternative to the industry standard use of talc for testing of gaps, leaks and contact though

Believe it or not, I do have some French chalk for my motorcycle tubed tyre activities. But the job of coating the sides of a pair of Jag 205/70/15s would probably use up what would otherwise last me ten years. It also probably sticks less well than grabbing a handful of soil and rubbing it around.

So, too refined by far for this rugby player, and pinching some of SWMBO's baby powder would risk a fate worse than death :-)

Pete

kingzetts · Post by **kingzetts** » Sun Jan 29, 2012 8:48 pm

I just thought I would update this thread.

I bought a set of 15" x 6" centre-laced Daytons which are now fitted with the standard 185x15's which were on my previous 15" x 5" wheels.

Interestingly, whereas the inner edges of the tyres were rubbing on the bump stops on the old wheels, they now clear the bump stops by at least 5mm, probably more. Clearly, the new wheels are not only wider, but also carry all the extra width and then some on the outside, and have more inner clearance.

They also look sooooo much better.

So no need for any angle grinder action on the bump stop mounts after all.....happy bunny!

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