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- - Finally Done It ( https://www.xt660.com/showthread.php?t=4816)

Quote:

Originally Posted by ejj (Post 124370)

I'm planning to change XTX wheels to my R. How do X wheels work in highway speeds (120km/h 75mph)? Is it more stabile than R wheels?

Stability is a product of bike geometry.
These two bikes are designed for different purposes and they are set up accordingly.

I have no experience of the above conversion, but, the XT (or any other bike) can be modified in a two simple ways to change the handling.

For more high speed stability it is generally better to have more "rake/caster angle" and "trail". The opposite is true for quick turning.

Please excuse me if you already know this:
"Rake" or "Caster angle" is the angle between the vertical and the steering centre line.
"Trail", if you imagine a line drawn through the centre of the steering head to the floor, then measure from that point to the centre of the tyre contact patch, that is the trail. It decreases when the rake decreases.

From the Yamaha web site:-
XT660R Caster angle 27.4 Deg, Trail 107mm. 225 mm fork travel.
XT660X Caster angle 26 Deg, Trail 94mm. 200 mm fork travel.
http://www.yamaha-motor.co.uk/Images...m46-326368.jpg
http://www.yamaha-motor.co.uk/Images...m46-358219.jpg
If you study the two pictures above you will notice that the forks are completely different. On the R the spindle is in front of the forks, on the X it is underneath. This produces more "Trail". The smaller the trail figure the easier it is to turn the wheel. The greater it is the more stable the bike becomes at speed.

If you think of a shopping trolley. The wheel is offset from the "steering" centre so no matter there the wheel is before you push it, it always ends up straight when you push it. Thats the effect of trail.

So: If you put a smaller from wheel on your R, you will lower the front of the bike and as a result decrease the rake and trail and the bike is likely to be less stable at speed but it will turn very easily.

If you still want to do it and find that the straight line stability is not so good, you could try lowering the rear to compensate for it.

A quick rough calculation of tyre and wheel size give an R wheel a diameter of 713mm and an X of 600 mm. Half of that for each (i.e spindle to edge) is 356 for the R and 300 for the X.

So fitting lowering bones to give about 50mm drop would be about right.

On top of this, the brake disc is smaller on the R for a very good reason, on a dirt bike you do not want the bike to be overbraked as it is designed to be used on loose surfaces, whereas the X is primarily for road use where there is a lot of grip and this can be used to stop quicker.

Hope this helps - if anyone thinks I am talking crap - please let me know.

OGR

Quote:

Originally Posted by Old Git ray (Post 124381)

Ray I have read this through for you and I can't find any crap anywhere :YellowWink_VZHUX5:

:newspaper: Good reading Ray.

One can also add spacers in the forks, or lower the forks through the triple clamps by 5mm.

I agree with the above comments, that's a well written and informative post, good stuff Ray!

Thank you for help.

I bought used X wheels (Whole set; rim's, tyres, brake discs, cogwheel etc...). I put X wheels to my R.

I did following modifications:
Front wheel:
-R's brake disc is in use
-Front wheel was about 5mm too much on the left (brake disc side). Local dealer re-centered wheel by setting the hub correctly to the rim (The spokes have re_adjusted)
-Front fork spacer (25mm)

Rear wheel:
Modification no needed

Other
-OTR lowering links (-30mm). I'm only 172cm, so lower bike is better to me anyway.
-Adjustable side stand
-smaller supermoto front fender

Enduro tyres are Continental TKC80 and they are quite poor in high way speeds.
Supermoto tyres are Metzerel Rennsport and bike is very stabile and nice drive on
asphalt road.

Now I have supermoto and enduro :)

guys I am still keen to try and put supermoto wheels onto my Z, will the front wheel from an X fit ??????

I can get a sticky rear tyre to fit my rear 17 rim so really I only need to convert the front wheel from 21 to 17

I just fancy doing this and I dont think there is a modern Tenere yet with supermoto wheels fitted so I just thought it would be fun.

I will run supermoto fun in the summer then grippy mud tyres in the winter with the 21 front.

any ideas maybe its too much bother or maybe I could just get a 17 front from another bike ???????:BaseballHat_LNY2EG:

Might be converting my XTR to use XTX wheels. Any new updates regarding this? Too bad its a pain to get hold on used XTX wheels here in Norway/Sweden...

Ok can i fit a 17" wheel to my xtz keeping the z forks?:woo:

Hiya guys!! My dumb question is whether I can go the other way ie can I fit the XT660R wheels to my XT660X??? It sounds like I could providing I have a complete set of wheels and discs and calipers from the R?????? I could then use the R wheels with semi knobblies for the winter and fit the X wheels with normal road tyres for the summer. Thanks for any comments.

Just spotted this thread after starting another! Sorry.

You guys who have fitted an X rear wheel; any problems fitting a 150 rear on it? It looks like a 160 might foul things but it sounds like you all have no trouble?