Does size matter?

[tony]

I want to get some New Girlings for the Desert QUB which the book states should be 12 inches. I can only find 12.4 inch would the extra .4 of an inch make much difference?

[John Wakefield]

Tony. In pactice the extra .4 inch will probably not make any significant difference to handling, but you need to check chain clearance over the top of the swinging arm. It will reduce the clearance there and may cause it rub on swinging arm pivot tube.

[tony]

I think the clearance would be okay - Hagon sell a 300mm shock which looks similar to the Girling so I could go for that.

[Brian Catt]

On my visits to the Pre-65 MX Club meetings, it seems common to add long teles and longer rear shocks to some bikes. Presumably this is to increase ground clearance, but on many bikes it destroys the inbuilt geometry of both the steering and chain run. I can remember one particular hot-shot losing his chain during both practice and racing due to fashion-following! Griffons react well to suspension tuning, where turn-in can be a problem eased by height alterations, but in any case, always consider the full swing arm movement and what will happen to the chain tension at full droop or full compression.

[tony]

Thanks I will do a mock up with some old ones to check clearance.

[David Mace]

Back when I was 16 I had a 250 Griffon with worn-out standard Girling shocks. My brother was doing schoolboy scrambling and had (what was then) state-of-the-art "Girling Gas Shox". on his bike. When he got a Yamaha monoshock his old bike was going unused so in my youthful ignorance I decided to fit the Gas Shox to my Griffon. They were considerably longer than standard and I could only just about squeeze them in. This of course raised the rear end. I knew nothing about the need to raise the front to compensate, and wouldn't have known how to. I compounded this folly by having very wide and low handlebars (I'd read in an American magazine that you should have the widest possible bars for maximum leverage ...) which forced my body weight to the front. The inevitable result was a bike that was subject to the most fearsom "tank slappers". As Brian Catt says above, care must be taken when doing things that change the basic geometry of a bike. That said I wouldn't have thought 0.4 inch extra would be a problem. Good luck!