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post #1 of 14 (permalink) Old 11-01-2016, 02:02 PM Thread Starter
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Question Front axle question....

Hi,

I recently bought a 2002 Sprint ST with about 35000 miles. The front tire needed changing, so I removed the front wheel and had my shop mount and balance another one.

Upon reassembly, something seems a little strange. Everything goes back together OK, and I torqued the front axle to the listed amount (I forget, but something like 50 ft lbs.) Before tightening the pinch bolts, I noticed that the wheel seems to have maybe 1 mm of play back and forth along the axle. This didn't seem quite right to me. In fact, before I tightened the pinch bolts up, I found that I could push inward on the outsides of the two fork tubes and get rid of that slack. So now with the pinch bolts tightened, there is no play left, but this still doesn't seem quite right to me.

I guess my general question is on the design of the axle. Is it designed to get torqued into the right side of the fork tube, and have the wheel, bearings, spacer, etc. relatively "loose"? I guess I had assumed that the bearings need some sort of preload (torque?) directly on them (like you would in typical tapered head bearings. This front axle setup doesn't seem to be like that. Is it designed that way, or is something not quite right here?

P.S. - I was pretty careful to take pix on disassembly, to make sure to get everything back where I found it. Nothing appears to be worn, and at least on one parts diagram I found, I don't appear to be missing any spacers, etc. in there. Any advice would be helpful...

I think you can go here to see the photos of the wheel and parts before it went back together, and what the ends of the axle look like after it was torqued and the pinch bolts tightened, etc.:
http://s1382.photobucket.com/user/sp...20front%20axle

Last edited by spaceboy3000; 11-01-2016 at 02:10 PM.
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post #2 of 14 (permalink) Old 11-01-2016, 03:05 PM
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Others will chime in here, but I'm pretty sure you will have a small amount of 'runout' on the axle when it is put together.

You need to go back and loosen the fork leg pinch bolts right away, and bounce the front a couple of times. Then re-tighten the pinch bolts. If you 'push inward' on the leg, you are putting a load on the internals that they aren't designed for, and the leg(s) will drag, and possible bind.

Biggest concern with the reassembly of the front is making sure you don't dork up the speedo drive. It's easy to do!
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post #3 of 14 (permalink) Old 11-02-2016, 11:09 AM Thread Starter
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Hi,

Thanks for the input. Yes, I did read about bouncing the front wheel with the pinch bolts loose and then re-tightening them. I tried that today. That didn't seem to make any difference. What I also noticed is that those pinch bolts basically don't do anything on my bike. With the pinch bolts tightened down, I can still squeeze the forks and the axle still freely moves in and out slightly (maybe 1 mm) on the side where you put the large allen bit in to torque it.

For the heck of it, I unscrewed the axle and mic'd the outer diameter of that shaft where the pinch bolts should hopefully be holding it and then mic'd the inside of that hole, and there is about 1 mm clearance between the two, and the pinch bolts can't seem to close that gap. That doesn't seem right to me. Here's another picture:

http://s1382.photobucket.com/user/sp...0pinch%20bolts

I feel like a simple solution would be to take some thin metal, like cutting up an aluminum beer can, to make a "sleeve" around that part of the axle, so that the pinch bolts will actually tighten down and keep that end of the axle in one spot, and also keep it from spinning. Is that necessary, or are these things just designed to run that loose? I might believe that was the case, except why would you put pinch bolts on this thing if they don't actually do anything?

BTW, the speedo sensor, etc, seems just fine - no probs there at all.

Sorry for all the questions, but I'm new to these bikes and this really seems a little odd....
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post #4 of 14 (permalink) Old 11-02-2016, 03:31 PM
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No they are not designed to run loose. It should be clamped. Something is not right. Could it have the wrong axle in ? I don't have a Sprint of that year. I have a 2008, and the axle measures 29mm at the end.
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post #5 of 14 (permalink) Old 11-02-2016, 03:49 PM
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The fork leg should DEFINITELY be clamping the axle with the pinch bolt at the bottom - there is something wrong with your fork leg if it is unable to clamp the axle there
As for the space, that in itself is irrelevant (and likely will differ slightly from one bike to the next) - everything references to the leg on the speedo side and the axle /bolt creates a compression force across the wheel bearings/spacer, that keeps wheel 'centering' referenced to the speedo side fork leg; then the other leg simply clamps to the axle; but again it SHOULD be clamping it.

Rather than installing a shim (and 1mm difference sounds HUGE to be honest) it would be better to just take a rotary tool with a fine blade and apply it to the 'slot' to open the width allowing it to close tighter when the bolts are torqued - even a fine hacksaw blade would do the job and you are not going to compromise anything.
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post #6 of 14 (permalink) Old 11-02-2016, 05:54 PM
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Quote:
Originally Posted by DaytonaDave View Post
No they are not designed to run loose. It should be clamped. Something is not right. Could it have the wrong axle in ? I don't have a Sprint of that year. I have a 2008, and the axle measures 29mm at the end.
I agree with Dave on this. Checking on Hermy's parts fiche, there was a front axle change(W/speedo drive) according to VIN number on/around the 2002 Sprint ST model yr. Time to do some checking before you screw up the fork leg.
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post #7 of 14 (permalink) Old 11-02-2016, 06:31 PM
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I was about to chime in and say that the Allen head means it's the correct one for an '02, but I looked at the fiche and it's a freakin' nightmare. It looks like they used several different axles on the '99-'01 bikes, some of which had internal Allen heads and others of which had external hexes. It appears that all '02-up bikes should use T2001252, but it also appears that that part should fit all Sprints from '99 to present and that is definitely not the case.

If you can get the bike's history, see if you can find out if the axle or forks were replaced and with what year parts; it really sounds like a mismatch to me. I sold my '00 a few months ago; I only have '04s now else I'd check the OD of the axles for you.

Cheers,
-Kit

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post #8 of 14 (permalink) Old 11-02-2016, 06:42 PM
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Only using the parts fiche as a guide, this bike could have the correct axle and different fork legs. What tha????
The OP needs a lot of willing help with measurements from owners of '02 st's from a common VIN period as the OP's bike!
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post #9 of 14 (permalink) Old 11-02-2016, 07:21 PM
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There is only one spindle (axle) for all 139277 thru 208166 - this is all 02-04 ST AND RS
Part number T2001252

There are two different forks leg part numbers - changes at serial 161318
However whatever the change it is irrelevant to this issue, since the spindle is common across the range.

Next the gen 1 - up to serial 139276
This uses three different spindles - the 'latest' of those is same part as that used on the 02-04 models;
The forks are consistent throughout the range and ALSO the same part number as the pre-161318 series of 02-04.

Therefor you can conclude that the spindle and fork diameters are consistent throughout the entire range of 99-04 Sprints.

I use this parts fiche for things like this - http://www.triumphcenteruppsala.se/i...6149#partslist
It is the best bar none for identifying the part number by specific serial number within an otherwise 'common' range of model.
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post #10 of 14 (permalink) Old 11-02-2016, 07:42 PM
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I don't remember the specifics, but I do remember finding out the hard way that the axles don't necessarily interchange between Gen 1 and Gen 2 Sprints. That's why I'm wondering if one or the other part has been replaced with something else that the fiche says should work.

Cheers,
-Kit

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