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help with fork installation
hi all, was hoping someone could help me with some advice...
i'm replacing the suspension fork on my 2006? GT avalance hardtail with a rigid as part of an upgrade to turn the bike into a mean commuting, pavement-dwelling machine. the steerer tube on the new fork is 40 mm longer than my old fork. should i cut it down to same size as old fork or add 40 mm of spacersabove my stem? also, can anyone tell me how the star nut system works...how do i go about getting a star nut into the new steerer tube correctly so that i can fit headset and top cap? can i get star nut out of old steerer tube and re-use in new steerer tube and how do you do this? any help much appreciated. thanks,
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Hi this is the best info I can give you - take your old fork and you new fork to you local bike shop it will take them 10 min tops, some may charge some may not.
the other thing is they will need to get the bottom bearing seat off the old fork and fit it to the new fork.
unless you have seen all done before I would not recommending doing it yourself
Whenever I replace a fork I always have a few rides before I start cutting the tube down. Add spacers in the meantime as you find you need to tighten it up then when you're sure it's spot on then cut the tube down.
Don't re-use star nuts. Remove old one with really long screwdriver or similar and bash it out. New one goes inside the Tube about a cm from the top and most do up with an Allen key. Main issue as Christoffa pointed out is removing the old bottom bearing seat from the steerer tube which requires a special tool then putting the new one on which I do with a length of PVC pipe that fits over my steerer tube and then hammer it on.
Any doubt then LBS is your friend!
When did a hammer and a cold chisel become a special tool?
Well when you get idiots that nick the steerer in the process the word "Special" really does come into play....
thanks for the advice fatboy. so the star nut always goes about 1 cm below top of tube? and i assume it just gets pushed in with a broom handle or similar? once i get the bottom bearing seat from my old fork can i put it onto my new fork or should i get a new bottom bearing incl seat? thanks again,
My super technical technique for star nut installation is to find a screwdriver (preferably someone elses) with a shaft that fits down the middle of the star nut. Place star nut/screwdriver assembly at top of steerer tube and then bash screwdriver handle with a hammer, which wedges the star nut in the steerer tube, until star nut is at the desired depth. Return screwdriver and feign ignorance as to why the handle is now rooted.
Having attempted fitting some new forks on a bike myself recently, I can offer thoughts on my experience.
Use a hammer/mallet and screwdriver to very gently tap the crown race off your old forks off (assuming you are keeping the same headset for your new forks). Don't try to bash it off all at once. A little bit at a time is best, to ensure you don't scratch or bend it.
Take note (or better still, make a diagram) of the order that all the individual headset pieces come off. That can be important.
You would want to fully assemble the new fork into your headset to measure off where everything goes before cutting anything.
Decide whether you want any spacers in the stack, as obviously once the steerer tube is cut, it is cut, and you are stuck with what you have. If you leave extra space in the tube measurement, you leave room to put a spacer below your handlebars which would make your frame geometry slacker. Or putting extra room for spacers above the handlebars comparatively makes the geometry less slack. Leave any extra room in multiples of either 5mm or 10mm, the size of your spacers. These spacers are $3 from CRC.
For cutting the steerer tube, you can buy a little cutting guide for hacksaws that would help making an exactly straight cut on the steerer tube. File down any burrs off the edges once it is cut. If you are unsure, get your LBS to do it.
The star nut is not really re-useable, I would recommend buying a new one, they are a $2 part. Only insert the star nut once the steerer is cut down. You can bash the star nut into the steerer tube yourself, or buy the correct $30 tool from CRC which would help guide it into your steerer tube straight. Hit it down the tube to a depth of about 5-10mm. It is possible to ruin the star nut by bashing it in and it slides around sideways. Or you could go to your friendly LBS, I am sure they would do this for free.
Always use a liberal amount of grease when re-packing the headset. Put grease on the steerer tube, on the crown race, and all the bearings. Even on the spacers, as these creak and groan if they are squashed side by side. Once repacked, wipe off the visual excess.
Once it is all together, you are likely to need to re-tighten or pull it apart again, as there may still be some small play in it.
Cheers.
thanks heaps for the constructive advice guys, it's all done and dusted, shmick and smooth as butter. happy days