tmcafe Posted June 21, 2009 Posted June 21, 2009 Just reinstalled my front wheel (had a new Diablo put on) when I noticed that the spacer between the right fork leg and the wheel (bearing) spins easily, though it doesn't seem to move along the axle. WTF? I've never had this happen. The only reason I can think of would be tightening the pinch bolts before the axle nut. I tightened the axle nut by hand barely snug, then clamped on the front brake and held it like that with a zip tie while I torqued the pinch bolts, then I torqued the axle nut (reason to do this would be to position the wheel so that the calipers grab more evenly--but my pads still rub against the disks so the front wheel won't spin more than about four revs (?) The shop manual is expectedly confusing, as it mentions tightening the nut first, then torquing the pinch bolts and then the nut. OTOH I know that some are adamant about tightening the pinch bolts first to center the wheel and prevent fork stiction. Any tips appreciated!
Guest ratchethack Posted June 21, 2009 Posted June 21, 2009 TMC, the spindle nut is ALWAYS fully torqued up FIRST, to clamp everything tight in "the stack" (including the spacer) before tightening the pinch bolts. This is the ONLY procedure that will prevent fork binding and stiction. After torquing the spindle nut, you should bounce the forks a few times to properly locate the fork lower on the spindle before tightening the pinch bolts. This should enable your rotors to spin properly without the pads dragging. Don't EVER clamp the brake on (or even apply the brake ONCE) before fully torquing the spindle nut OR tightening the pinch bolts! You want the fork to find its natural position without anything influencing it. The rotors will stay where they took their last "set" on the rotor carriers and semi-floating buttons unless they are forced out of position. If you've disturbed the "set" by clamping the brake on as you described before fully torquing the spindle nut, this can force the rotors out of correct lateral orientation. If this is the case, the brakes will tend to pulse and drag unless or until the rotors properly "re-set" on the road. Hope this helps.
Flyboy Posted June 21, 2009 Posted June 21, 2009 Tighten the spindle (Axle) nut first before the pinch bolts. Problem will be solved.
tmcafe Posted June 22, 2009 Author Posted June 22, 2009 Thanks RH and FB. Tightening the axle nut first obviously makes sense as it eliminates any play between fork bottoms, spacer, and wheel. Actually in my case the problem was solved kind of half way through: I tightened the axle nut up to the point where it started spinning, as there isn't anything at the opposite end to counter the nut torque (unless you stick something in one of those two semicircular notches on the edge and align it to stop against the split in the fork bottoms. So the axle got tight enough so nothing was loose on the axle, then torqued the pinch bolts, then finally the nut was torqued easily. But the effing brakes are still rubbing against rotors. Maybe the calipers could use some cleaning.
Flyboy Posted June 22, 2009 Posted June 22, 2009 It is quite normal for the pads to slightly rub the rotors. Getting four revolutions before stopping is better than most. No worries. Go ride as long as the brake lever feels good when applying the brakes. Thanks RH and FB. Tightening the axle nut first obviously makes sense as it eliminates any play between fork bottoms, spacer, and wheel. Actually in my case the problem was solved kind of half way through: I tightened the axle nut up to the point where it started spinning, as there isn't anything at the opposite end to counter the nut torque (unless you stick something in one of those two semicircular notches on the edge and align it to stop against the split in the fork bottoms. So the axle got tight enough so nothing was loose on the axle, then torqued the pinch bolts, then finally the nut was torqued easily. But the effing brakes are still rubbing against rotors. Maybe the calipers could use some cleaning.
Baldini Posted June 22, 2009 Posted June 22, 2009 ...there isn't anything at the opposite end to counter the nut torque... Has the axle head not got a hexagonal socket (could be blanked off with a rubber cap). If it has, you put a hex key/socket in this & tighten axle nut against that (bike tool kit should contain short piece of hex bar for this purpose). You MUST torque axle nut up properly against bearing/spacers/axle head stack. Ratchethack's post above gives correct procedure. KB
dlaing Posted June 22, 2009 Posted June 22, 2009 You MUST torque axle nut up properly against bearing/spacers/axle head stack. And properly means such that torquing does not increase bearing friction. If it does, then you need a longer bearing spacer. I don't think bearing spacer length is a problem at the front wheel, but some had too short of a spacer at the rear, causing binding at the bearings and bearing failure.
tmcafe Posted June 22, 2009 Author Posted June 22, 2009 Thanks for the feedback. The wheel did at most four turns when spun with force by foot. I ve seen much better. The axle has a larger diameter section on the left with nothing for a hex tool like in the rear. Instead it has two opposite holes about 1 in from edge (probably to insert a rod to pull it out easier) and two semicircular notches on the edge--the diams of these are about 1/4 in. I assume the only way the axle could be torqued to 90 as specd would be to insert a thin tip something like a flat screwdriver to align either notch with the split in the fork bottom and jam it against it while nut is being torqued. Not sure i understand how a shorter spacer (fortunately both front and rear spacers seem to work fine) would increase bearing friction. Would it be uneven pressure?
Guest ratchethack Posted June 22, 2009 Posted June 22, 2009 The axle has a larger diameter section on the left with nothing for a hex tool like in the rear. Instead it has two opposite holes about 1 in from edge (probably to insert a rod to pull it out easier) and two semicircular notches on the edge--the diams of these are about 1/4 in. I assume the only way the axle could be torqued to 90 as specd would be to insert a thin tip something like a flat screwdriver to align either notch with the split in the fork bottom and jam it against it while nut is being torqued. TMC, I'm not picturing all of this^ very well (the 2 semicircular notches are beyond me ), but I think you might be missing something here. I've had the front wheel off and back on a '04 LM for a tire change, and don't recall anything at all unusual about securing the spindle (axle) for proper torquing. The chances that Guzzi designed a front spindle that couldn't be fully torqued up (even without a torque wrench) with the tools provided in the tool kit are somewhere near slim and ZIP, and nothing needs to be aligned or jammed into the pinch-slot in the fork lower. Many V11's (including mine) provide a through-hole in the spindle so a rod can be inserted to secure it for torquing at the nut end. The through-hole is not there to pull the spindle out. Anything you can put in there that fits will do for torquing the spindle nut. I typically use the shaft of a large crosspoint screwdriver that just fits, because it's handy in my home shop, and it's long enough to provide good leverage. I assume the only way the axle could be torqued to 90 as specd . . . FWIW, my Guzzi manual spec's 70 lbs./ft. (90-100 Nm) torque for the front spindle and 88 lbs./ft. (120 Nm) for the rear spindle. Not sure i understand how a shorter spacer (fortunately both front and rear spacers seem to work fine) would increase bearing friction. Would it be uneven pressure? The OE spacers have been known to crush and deform under excessive spindle torque. If a spacer has been shortened in this manner, this puts fatal side-loads on wheel bearings, and they typically head South in short order. The fix is a new spacer cut to the proper length (the distance between bearing registers in the wheel) with new bearings. Many threads on this topic. If you've torqued the front spindle nut up to 90 lbs./ft., you might be OK, but I'd keep a keen weather eye on it for symptoms of the bearings going out. Hope this helps.
Baldini Posted June 22, 2009 Posted June 22, 2009 tmcafe, you have Ohlins forks? Mine look like this. Yours are different?
Guest ratchethack Posted June 22, 2009 Posted June 22, 2009 tmcafe, you have Ohlins forks? Mine look like this. Yours are different? Hm. This would explain a few things, and would seem to match up with the photo in his avatar. And yet, he mentions a spindle nut, and this fork doesn't use one. . .
tmcafe Posted June 22, 2009 Author Posted June 22, 2009 tmcafe, you have Ohlins forks? Mine look like this. Yours are different?Thanks Baldini and RH. Yes Ohlins stock but mines are diff though: 30 mm nut and washer instead of the Allen, and those two slots on edge of opposite wider end whereas yours seems to thread into right fork bottom. Four pinch bolts two per fork where yours has one set on right. There was a pic of that kind of axle maybe I ll find it. Might be common with Ducati. Also if you find a large pic of a Coppa (the official pics of the Cafe don't seem to show the axle nut setup on mine!--typical Luigi) you may be able to discern the large axle nut on the right fork bottom. As for the through hole RH mentions it can't be used for torquing as it's further in where axle is inside fork bottom.
savagehenry Posted June 22, 2009 Posted June 22, 2009 I've got the Ohlins hollow front axle too. Can't look at the one I made at the moment, but it's just a piece of 1/4 inch thick x 1 inch wide aluminum (if memory serves me correctly) x 3 or 4 inches long, with the corners ground down to a radius that fits in those half circle slots, hold it with a cresent wrench for the torqueing part of the exercise. Easy to make with a saw and file. Doesn't have to be perfect, just close enough.
tmcafe Posted June 22, 2009 Author Posted June 22, 2009 I've got the Ohlins hollow front axle too. Can't look at the one I made at the moment, but it's just a piece of 1/4 inch thick x 1 inch wide aluminum (if memory serves me correctly) x 3 or 4 inches long, with the corners ground down to a radius that fits in those half circle slots, hold it with a cresent wrench for the torqueing part of the exercise. Easy to make with a saw and file. Doesn't have to be perfect, just close enough. Thanks that soun ds like a useful tool. Still wondering why do some folks mention the potential issue of putting too much pressure on the wheel bearings if the axle is torqued before the pinch bolts?
raz Posted June 22, 2009 Posted June 22, 2009 Still wondering why do some folks mention the potential issue of putting too much pressure on the wheel bearings if the axle is torqued before the pinch bolts? I can't see that happen. Torquing the pinch bolts before the axle would be just wierd. Like tightening the lock nuts before setting valve clearance FWIW I heard of more than one Ducati rider over torquing the pinch bolts to a degree it actually caused the hollow axle to go oval
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