|Wheel arch widths

[Fspp369]

Does anyone have any information that will stop me making an expensive mistake by trying to widen my wheel arches too much.
I want to add slightly larger tyres and increase offset in the rim by no more than 20mm. just want it to be a gentle widening rather than a race car look
Pete

[bitsobrits]

You can put 215/70 or 215/65 tires on 6.5 wheels with the right offset without arch mods (I've done both). How wide are you wanting to go?

The wheel arch is comprised of the outer skin and an inner shell which is welded to the outer at the wheel arch edge. As such, any significant widening of the the rear arch involves cutting, fabrication, and welding in the arch area, which not only impacts the paint on the car quarters, but also perhaps the interior (heat damage). Then there is the considerable negative impact to the car's value. Unless you are Leonardo Fioravanti, I would avoid trying to change the lines on an E.

FWIW The primary point of interference with a wider tire and a stock wheel arch is at the rear of the opening, due to the taper of the E type body front to rear. One of my earlier E types came to me with 225/60 section tires mounted, and some PO had ground the rear horizontal spot welded 'lip' down to gain clearance without otherwise changing the bodywork. Not a recommendation, just a point of information.

[Fspp369]

At the moment I'm not too bothered by welding issues !!
Cheers

[bitsobrits]

Ah, no worries indeed. And I see you have an S3, which starts with wider arches. My earlier guidance only applies to S1/S2 cars. With an S3 it seems to me you might gain some useful clearance by just modifying the inner arch. But it all depends on the width of tire you want and how much offset can be had in available wheels. MWS, who built my 6.5" wheels, set them up so no mods at all are required. At the time I bought them years ago, the forum consensus was anything wider than 6.0" wasn't possible.

I've found wheel mockup tools can be useful when determining "what fits".
(https://www.amazon.com/wheel-fitment-to ... tment+tool).
I typically just use electrical wire (attached to a hub and bent in the profile of a tire) as it's soft and easy to work.

[Fspp369]

Ahh well you see Steve that’s why I ask the question in the S3 bit of the forum, but I’m thankful for the info about Amazon gadgets.. I’ll make one now I’ve seen the pattern.
It’s all go isn’t it.Cheers

[lowact]

You can put much wider wheels on an S3 without flaring the guards if you have stud hubs instead of splined hubs. With splined hubs, the wheel must be square and aligned with the axle hub almost 4 cm before it is pushed home. With the wheel hanging, the gap between the tyre (215/70R15 on oem 6.5” rims) and the wheel arch flange is ~5 cm, i.e only 1 cm more than the 4 cm required for installation. So, with splined hubs, you can only alter the wheel rim (relative to the hub) by up to 1 cm before flaring would be required.
No such constraints with stud hubs, you tilt the wheel in onto the top stud and swing it straight, directly into position, i.e, sliding it in 4 cm is not required therefore the full 5 cm clearance provided by the original unaltered rear mudguards is available for wider wheels &/or increased rim outset. Considering that there is also opportunity for a small increase in width on the inside (constraints are bump stop and lower control arm grease nipple) after allowing a nominal clearance for mudslinging, wheel widths up to 8 inches could be accommodated without flaring the guards, if stud hubs are fitted and wheel offset designed accordingly.
If you like the dished-wheel look, stud hubs have the advantage that there is no massively protruding splined hub that fills in any dish.
All the above is subject to the tyres not being too wide for the wheels. Chasing the chunky look, wider tyres on original rims, makes it easier for the hubs to move laterally relative to the tread, extremely detrimental to handling. Modern practice has the rims wider than any part of the tyre, benefits handling, efficiency and tyre life.

[Fspp369]

Colin, thank for those concise thoughts.
I am not a great lover of the “chunky look” per se, but would like to give my finished car a slightly wider, lower , slightly more “racey” appearance. …a difficult compromise.
I do have another consideration, in that the rear hubs are from and XJ40 (to get outboard discs ) so I think are slightly “outboard” already. They’re part of a studded wheel arrangement at present, but I would like to end up with wires.
I am not too bothered about getting MUCH wider tyres, but the std S3 does tend to be look a little perched on a knife edge to me.. (not as pronounced as an S1 ) But I definitely do not want the Chip Foose look…maybe a little too far but still good looking..
The racing lightweight look is also too far for a road car albeit great on the track.

Oh decisions,decisions,..

I could also add a rear wing and front canard fins I suppose !! ????….NO!!