Is shock mount an M12 ?

[FFMan]

By some chance it looks as if these http://tvrparts.co.uk/tvr-parts/part-details/tvr-c... are an exact match for a Yamaha XT350 lower shock absorber bush.

Can anyone confirm or deny if the bolt fitting is M12 ?

thanks

[stevesprint]

FFMan said:

Can anyone confirm or deny if the bolt fitting is M12 ?

The factory shock bolts are 1/2 UNF

[FFMan]

thanks - might work with a bit of fettling if I can't fund the bush elsewhere.

thanks

[ray von]

I don't know if I've misunderstood your post, but please don't tell me you're going to fit an M12 bolt instead of a 1/2" UNF

[FFMan]

no I wouldn't do that to my TVR for sure.

I was considering the whether I could use the TVR bush on the Yamaha suspension, but as it turns out I think I found a supplier who should have the right parts. I had to cut away the bolt as it was seized solid to the bush on the Yamaha and I didn't want to have to buy a complete new damper

[ray von]

Ah I see. I did hear a horror story a few years ago where someone had completely rebuilt his Griff and had used metric bolts

[portzi]

ray von said:

Ah I see. I did hear a horror story a few years ago where someone had completely rebuilt his Griff and had used metric bolts

Unfortunately that is a gamble when purchasing a car from a home mechanic or even a specialist!! who has very little knowledge of the TVR quirks ,0.7 mm different between 1/2 inch UNF and M12!!!!!

[ray von]

portzi said:

ray von said:

Ah I see. I did hear a horror story a few years ago where someone had completely rebuilt his Griff and had used metric bolts

Unfortunately that is a gamble when purchasing a car from a home mechanic or even a specialist!! who has very little knowledge of the TVR quirks ,0.7 mm different between 1/2 inch UNF and M12!!!!!

the car was done by someone who "rebuilds and restores cars for a living mate. It's what I do, I know what I'm doing" Then it was put right by someone who really knew what they were doing

[portzi]

ray von said:

portzi said:

ray von said:

Ah I see. I did hear a horror story a few years ago where someone had completely rebuilt his Griff and had used metric bolts

Unfortunately that is a gamble when purchasing a car from a home mechanic or even a specialist!! who has very little knowledge of the TVR quirks ,0.7 mm different between 1/2 inch UNF and M12!!!!!

the car was done by someone who "rebuilds and restores cars for a living mate. It's what I do, I know what I'm doing" Then it was put right by someone who really knew what they were doing

TVR'S hey pal, l am sure Peter wheeler insisted that they were built with imperial sizes and not metric . What bolt sizes are the T-cars built with?

[stevesprint]

portzi said:

TVR'S hey pal, l am sure Peter wheeler insisted that they were built with imperial sizes and not metric . What bolt sizes are the T-cars built with?

Griffs were built with both metric and imperial sizes. The chassis to body and exhaust tray bolts are M10 and the chassis to suspension bolts are 7/16unc and 1/2unf.

[portzi]

stevesprint said:

portzi said:

TVR'S hey pal, l am sure Peter wheeler insisted that they were built with imperial sizes and not metric . What bolt sizes are the T-cars built with?

Griffs were built with both metric and imperial sizes. The chassis to body and exhaust tray bolts are M10 and the chassis to suspension bolts are 7/16unc and 1/2unf.

Why does that not surprise me Steve, TVR mixing metric and imperial any engineers worst nightmare.

[ray von]

portzi said:

stevesprint said:

portzi said:

TVR'S hey pal, l am sure Peter wheeler insisted that they were built with imperial sizes and not metric . What bolt sizes are the T-cars built with?

Griffs were built with both metric and imperial sizes. The chassis to body and exhaust tray bolts are M10 and the chassis to suspension bolts are 7/16unc and 1/2unf.

Why does that not surprise me Steve, TVR mixing metric and imperial any engineers worst nightmare.

It all adds to the fun pwopa engineers spot this sort of thing straight away, I struggle with everything else though
P.S. IIRC 7/16 UNF not UNC

[stevesprint]

ray von said:

P.S. IIRC 7/16 UNF not UNC

Sorry my mistake, I was caught out as they are different size bolts but with the same Threads Per Inch of 20.

I've since found this table that shows 7/16 and 1/2 with 20 TPI and therefore both are UNF.

Threads Per Inch (TPI) Table

Bolt	Coarse Thread	Fine Thread
Size	UNC	UNF
1/4	20	28
5/16	18	24
3/8	16	24
7/16	14	20
1/2	13	20
9/16	12	18
5/8	11	18
3/4	10	16
7/8	9	14
1	8	12
1-1/8	7	12
1-1/4	7	12
1-3/8	6	12
1-1/2	6	12