Rear wheel adjusted as far forward as tire clearance will allow

I wanted to do some rambling (wife is asking to go fix up and clean

out the pound) so, I picked something important that hasn't been

talked about in a while.

Rear tire placement (adjustment) makes a big difference in

cornering. I over looked this in favor of bigger tires at time (Tera

Flex, IRC M5B, Michelin Desert) for the riding I was doing or trying

to do. I put a Dunlop 756 on for the trip down to Baja 250 earlier

this year and was running 15/49 gearing with a stock number of links

(110). This put the axle all the way forward to what Johnny Campbell

runs his axle. What a difference in carving a turn. In the sand I

can stand up and lay the bike down in second (this is fast for me, I

do mean lay the bike over) and throw a major roooost, wipping the

bike around. There is no way I could do this with the axle back at

mid point and with the axle all the way back won't even think of

laying the bike down. With the tire forward I can stand on the pegs

and just spin around without high siding. Something to try if you

miss the way you can carve a corner with a CR250. No I couldn't cut

it near to what my son could on his CR80 but, with the axle all the

way forward I can slide though a burm shooting a roost and that is

just plain fun pig squeeling.

I brought this up for those that are looking for more and give

something to look into. It's nohing new. It's even in the service

book you get with the BRP. Honda Race team makes this a major

priority.

"Keep the rear wheel adjusted as far forward as tire clearance

allows. The bike turns and handles better and is more stable with

the wheel adjusted closer to the swingarm pivot."

http://xr650r.net/bruce_ogilvie.htm

I've heard that before, but wouldn't you have to take a link out of the stock chain to do that with stock gearing?

4Takt

I'm running a 15/46 with a 110 link chain and it's about half way along the adjuster. I reckon a 49 would put it right near the front of the adjustment.

BWB .. did you notice any effect on high-speed straight stability with the wheelbase shortened up ?

BWB .. did you notice any effect on high-speed straight stability with the wheelbase shortened up ?

I can't get what is what on that because once I went 680cc the front tire is a lot harder to keep on the ground. I think it's less "high-speed straight stability" in terms of the bike not wanting to stay where you point it but, not more head shake. The bike will respond to turning way faster with less effort but, not twitchy like a KTM525. I have noticed I have to ride the bike more (more input from me) then just point and shoot but, if that is caused by more power also :D or both :D It seems the most noticable change is in the mid RPM torque range through the whoops. Before 680cc I just went wishing for more power to straighten out the bike when things went wrong but, now there is more power with the front tire floating more and the wheel base shorter making it turn easier.....requiring more input from me. The bike is more MX in turning but still not as much as the KTM or CR's

BWB60, Well i have 14/50 and 112 links and i tried to see if i could remove 2 links and it does not look like it will work, Did you remove the nuts on the rear adjusters for the axle blocks..... :D

I haven't cut the chain till I'm sure it'll work, looks like about a 1/8 of an inch from working, But then I probly won't have enough chain slack....

You stated your gearing was 15/49 and I'm thinkin thats the same space, link wise as 14/50........

No, I still have my nuts last time I looked :D:D

I have the nuts on and the adjuster all the way in. New chain and sprockets. 15/49. Rethal Counter shaft and Ironman rear. The chain is able to touch the rubber at the back of the chain slider. Thats were I run it loose enough to jump. I do know that one tooth on the counter shaft sprocket dose not move the cain the same as one tooth on the rear sprocket. So, 14/50 won't be the same as 15/49. How much difference I don't know but, it has to do with the size ratio difference. One tooth of the counter shaft spocket doesn't make the sprocket bigger as one tooth on the rear sprocket. You have added two teeth more to the rear sprocket over stock. I added on to the rear and one to the counter shaft.

Well, I'm glad you still have your nuts... :D

Thanks for info........ :D

:D Great Post :D

There is a gearing calculator which also gives the required length of chain here:

http://www.4strokes.com/tech/gearing_calc.xls

It appears to be set up for the XR650R and is accurate for all that i've been able to test.

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