August 7th, 2016, 02:06 PM
Joined: Nov 2001
From: Ely, England
that was very nearly hell! I guess I've been lucky to here and knew the answers before I even got the questions but today was the first time I THOUGHT I knew....
well anyway, I am "stato" to those of you who speak English AA2ndL a "stato" is a statistics man and usually I'm quite good at it.
My first surprise was finding that there was a 25mm (1 inch) difference in height of the tyre on a 20" compared to a 21" wheel. I had it down as 12mm from old "statistics" I have written down. 12mm I can get over but 25mm? Oh dear! that meant the wheel spindle was 12mm higher after we fitted the new supa-dupa 21" wheel and Mich Starcross 5 tyre.
I'd counted on 3-4mm...........
anyway, first test was 'as is' as always and it was fine. Rob rated Dan the passenger highly and he then asked what did we want to test. hoping that the 43mm carb was ready I had to disappoint him and he then bounced me with the 21" wheel project. I must be weak and gave in instantly.
so we fitted the 21" instead of the 20" and I knew it was going to be shit but WTF, Rob said;"2 let's go"... and he was right, instead of trying stuff before you know it is shit....shit, why not wait to prove it's shit and then you can do something!
so we rode it like that and it was bucking and bouncing everywhere. At present we run a soft and hard spring combined on the front and as the front was too high I thought we'd soften it using the springs.
normally you'd back off the preload but we have none so there was no alternative but to fit the other soft shock from set number 2.
this made the outfit tip up on lefts as the front collapsed and the rear tipped over it and the Sidecar wheel. nasty!
we then tried 12psi and only 1mm preload on the starting shocks (a 21.5 and a 23/44 again) but alas no good.
I realised we had increased the trail and declared it as a 'chassis only' issue. this wasn't going to be cured with clickers and springs no sir-ee!
so I asked for the loop to go to the front hole and reduce the trail. this really made it handle way better.... we were nearly there.
however, even though the wheel had moved forward 15mm it appeared that the new more laid down angle of the front shocks meant that the bike sat at the same height and now the springs were infact - weaker!
so we now tried the two STRONG springs - the 23/44s and this was lovely! it was decided this would make a great front set up for rough tracks, chisel edged shyte and whooped out sand. so in 8 weeks it may get used again at Canada Heights!!!! we'll let you know then!
our last test was, as you can imagine for a professional set-up... AS WAS.
but Rob insisted on just 12psi in his own 20" front Maxxis and that went well.
my 21" gave them the quickest lap they did all day by over 1 second............... and in the meantime, the team that came 6th at the British a fortnight ago were going round 7 seconds a lap slower.
we can make this 21" work better but we need holes drilling above the front shocks and above and between the pivot points at the bottom of the solid fork legs. THEN we can get it to handle.
Last edited by Taffy; August 7th, 2016 at 02:14 PM.