Gurston Down hillclimb

[Tree man]

Just come back from a good weekends racing at Gurston Down hillclimb. I managed to dodge the heavy showers to get in several dry runs. A tentative start gave way to more aggresion and a PB as I realised the car was not about spear off into the scenery, helped by the new Yoko tyres.
http://www.youtube.com/watch?v=oFpjS3KoXF4
It's the type of hill that rewards power and I need more, so I have decided to investigate double IDA carbs as a more cost effective alternative to triple DCNF's. Some suspension mods and wider 7" rims (not easy to find with the MGC stud pattern) are also in the budget to keep the tyres under control - obviously I have more than enough talent

[Greybags]

Hi Treeman ..

Another great video for the collection.

I would have thought wheels would be fairly easy to source as the MGC shares the same stud layout and PCD as the Chevy and Jag, 5 stud 4.75" PCD

Look forward to seeing the next fantastic installment..

Grahame

[Tree man]

I originally though that but on investigation the MGC is a 4.5" PCD. Same as the Ford 5 stud on old Granada's, Zephyr's, Mustang's, etc. An MBG hub with an extra stud in effect. Given the lack of choice using the above info' I'll be happily corrected if I'm off track

[Greybags]

Hi Treeman..

Good question, so I have gone off and done some more checking as 4.75 is what I have written in my "Boys book of Interesting Bits".

I have checked a further number of trusted MG sources and 8 out of 10 say 4.75, but a couple say 4.5 (MGB with an extra stud)..

So thought the only way to confirm was to measure the spare wheel on mine which was out of the car in the garage...

Following the measuring PCD guide here http://www.mwsint.com/TechCalcStuds.asp on the MWS wheel site, I get a measurement of approx 71mm, which according to their chart is a PCD of 4.75"

So would have to say that the Chevy/Jag pattern wheel is still correct ..

Possiibly the safest way is to measure one of your own wheels, but cant imagine that even Gilbern had 2 different wheel patterns

[trippdl]

Hello TreeMan -

Just as important as the bolt pattern - go measure the backspacing. This is the distance from the outside of the rear bead on the rim to the mating surface. On my (now ex-)Genie, with the standard wires, there was very little clearance between the back of the tyre and the chassis; ie, if a new set of wheels has a larger backset, the tyre would have rubbed against the car. On most of the Chevy (5 x 4-3/4) wheels, the backspacing is 2". The other significant number is the offset, ie, where is the mating surface relative to the centreline of the wheel. Check these numbers, and report back...

[rocketman]

The PCD on BMW wheels is only 0.6mm different than the Jag, I believe you can buy special washers to compensate. The MGC is the same as the Jag, I have spent some time investigating the various options as Part of my Mk3 project, which now has an XJS rear axle setup.

Stu.