| Author | Message | ||
     Gotj |
It will be interesting to see how the rear wheel bearings on the XT fare. With less travel, the higher belt loads of the X will be reduced and the bearing life may mirror that of the other XB 54" chassis. That assumes of course that the bearing failure is related to the higher belt loads which makes a lot of sense to me. The other issue that also rings true is the spacer being just slightly too short thus imparting a side load on the bearings. The issue could be quality control such that many of the spacers are just a bit longer (while still in spec) so that abnormal bearing failure does not occur. Possibly, the spacer for the XT wheels is sourced from another supplier and is the correct length. In all my dirt bike years, I never had undamaged bearings turn as hard as those on my Uly's rear wheel. If I were to (or when I) replace the bearings, I would be inclined to shim the spacer to take off the side load. | ||
| Mark_weiss |
Does the XT use a different belt, pulleys, tensioner, or swingarm? If not, the basic geometry will be the same as the X. In fact, the XT should actually run somewhat higher average belt loads. The distance between the transmission output and the rear axle is greatest at full compression of the rear suspension and the distance decreases as the suspension extends. With it's shorter rear wheel travel, the XT will be relatively less extended than an X, most of the time. Mark in Arizona | ||
| Jlnance |
The distance between the transmission output and the rear axle is greatest at full compression of the rear suspension For every motorcycle except a Buell  | ||
| Mark_weiss |
?????? With the swingarm pivot behind the countershaft, compressing the suspension to (nearly)align the countershaft, swingarm pivot, and rear axle, should create a greater distance than allowing the swingarm to drop, which should allow the axle to swing somewhat closer to the countershaft. If this were not so, the tensioner pulley would not need to be used to create a longer belt path as the rear suspension rebounds. No? Mark in Arizona | ||
| Jlnance |
Yes. Thats why the pulley is there. If you make it the right size and put it in the right place, it takes up all the slack as the swingarm comes up: http://www.google.com/patents?vid=USPAT6866112
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| Jlnance |
Actually you were right. The transmission to axle distance does change as you state. It's just that the belt tension isn't supposed to as a result of that. | ||
| Gotj |
The distance between the countershaft pulley and rear wheel pulley is greatest when their centers are in alignment with the swingarm pivot, not at full compression. What prompted my post was the fact discussed in another thread that the Uly places something like 25% additional load on the belt at some point in the swingarm's travel compared to the other XB 54" models. I don't recall the position of the swingarm where that occurs. If it occurs at full compression or between full compression and full extension, then the XT bearing failure rate would be the same (or worse) as the Uly. If it occurs at full extension, then the XT failure rate should be less. | ||
| Jlnance |
Gotj - Nothing else has bearing failures like the 12X. The Ss and TT are the closest to the XT I would think, and I've heard no stories of bearing failures there. | ||
| Ronmold |
I would think the wheels are the big difference on the X compared to the XT or other Buells. I'm thinking the thicker aluminum of the wheels expands more than the thinner "street" wheels when they warm-up and puts excessive side thrust on the bearing. |
