Shocks

[Guest oshiney2]

hi guys been having problems with the height at the rear end of my 2b plus after changing my 17inch wheels for 15 inch wheels it seems to have got worse \ it has coil overs all round the issue is that its been hitting of the ground at any-time there's a dip in the road its so maddening my question is if i heighten and stiffen the rear do i have to heighten the front the same distance. the part that's hitting is the bolt that holds the swinging arm to the floor hope you know what i mean anyone help

[Snapperpaul]

By reducing the overall wheel diameter you have effectively dropped the offending bolts closer to the ground.

I would start with harder springs and if you have adjustable shock go up on the resistance a few clicks at a time

[cb750]

When you swapped to 15 inch wheels did you increase the ratio on the tyres to keep the same overall diameter of the wheel and tyre assembly or have you ended up with a smaller overall diameter?

[Guest 2b cruising]

It is quite obvious you are now riding lower than you used to.

I get a good and problem free ride with my 195 x 50 x 15 tyres.

The Hight of my car from the ground is, just in front of rear wheel arch side panel bottom edge to ground is 7".

Just behind the front wheel the same measurement is 6" from bottom edge of panel to ground.

I measured this before changing my shocks as the previous owner had it professional set at a race prep engineers shop. All the setting details are on the worksheet kept in the cars history file.

After adjusting shock hight to the same as the old one and then rechecking body hight, I have had no problems at all.

Setting ride hight as such allows you to have a low setting on stiffness for road use giving a soft and comfortable ride.

If going on the track, or going for a "spirited" drive, you can stiffen the shocks by the same number of clicks on each side. Adjust back to road use after having your fun.

This way you will illimiminate a lot of future back ache from doing long runs in a stiff set up car.

If you can set up in the same way, you should get a bump free ride.

If you don't have ride hight adjustment, follow snappers idea of stiffening. This will help stopping you from grounding out on bumpy surfaces. It won't lift your ride hight.

Harder springs will help lift the car, but won't help ride comfort.

Hope this helps somewhat and you can solve your problems.

Ken.

[Guest whiz]

It was the strawberry tart you had on Sunday mate. Don't blame the car lol

[speedtripledan]

my 2 b was always hitting the ground on either the plough or subframe, especially 2 up. Only cure i found was to sell it....

[Snapperpaul]

Nobody has answered the op's post, if it was hitting originally with the 17's and is worse with the 15's it still point to to soft rear springs

Possibly some compliant bump stops would also help

[Bob Tucker]

What make of coilovers do you have?

If they are the Zimmerides, they could well be part of the problem.

Post up a bit more info.

Distance from ground to bottom of sill just in front of the rear wheel arch

should be around 7 inches.

Comparing the 17 & 15 inch tyre sizes will also help diagnose the problem.

[Guest JammyJim]

Have you got the large cups over doughnut at suspension mount.is it where it's hitting ground I had this problem and modified cup but removing 40 mm and welding flat washer to it

[Guest oshiney2]

hi i removed the cups and welded the bolt to a flat thick plate but it was that low it wore away the weld when hitting the ground it was working fine till i changed the wheels so i do think its just a height problem thanks

[Guest oshiney2]

my 2 b was always hitting the ground on either the plough or subframe, especially 2 up. Only cure i found was to sell it....

well thanks dan that was really helpful lol

[Guest oshiney2]

thanks for all your help guys i will let you know how i got on once i have tried your suggestions

[Guest oshiney2]

hi someone was asking for the tyre sizes past and present 17 inch size was 205/40/17 now 15 inch is 195/50/r15 does this help work out some figures thanks

[Bob Tucker]

This site does provide some help.

http://tire-size-conversion.com/tyre-size-calculator/

It shows a diameter of 23.5" for the 17" tyre

& 22.7" for the 15 inch, so 0.4" lower.....probably not the only reason.

[Bob Tucker]

We seem to get different results....

http://www.willtheyfit.com/index.php?width=205&aspect=40&diameter=17&wheelwidth=&offset=&width2=195&aspect2=50&diameter2=15&wheelwidth2=&offset2=#content