Fork Question

[Plax]

I want to change the forks on my MTB. Currently suspension fork (100mm travel) with no lockout. I want to put rigid forks on.
It's an 18" Carrera Vulcan with V-brakes.

I'm not sure what I need to get. Is it 1 1/8" and will I need to cut the stem at all?

I was thinking something like this;
http://cgi.ebay.co.uk/MTB-rigid-ste...sure_cycling_bikeparts_SR?hash=item3a57655ca9

but the description says it is only for a quill stem and not Ahead, and I'm not sure what kind of stem I have.

Any help appreciated.

Ta

 

[Plax]

This maybe?
http://cgi.ebay.co.uk/BANKRUPT-26-1...sure_cycling_bikeparts_SR?hash=item27ac2e9e6a

 

[GilesM]

Example of A-Head stem, with this type, the stem clamps onto the top of a threadless fork steerer. The A-Head stem is the locking system that holds the headset together and the forks in the headtube. If you remove the stem, the forks will fall out and the headset will come apart.
http://www.chainreactioncycles.com/Models.aspx?ModelID=6286

Example of quill stem, stem is inserted inside the steerer tube, this is used with a threaded fork steerer, you can remove a quill stem without the forks or headset all coming apart.
http://www.raleigh.co.uk/p_details.aspx?id=2554

The two e-bay links you have shown are both for quill stems as the fork steerer is threaded.

Have a look and workout if you need a threaded or non threaded fork steerer. When you replace the fork, you need to check that the fork steerer on the new fork is long enough, before buying the forks, if it's too long, you can easily cut it down with a hacksaw. If you need threaded fork steerer, make sure the thread comes down far enough.

HTH

 

[TheDoctor]

IIRC you've got an Aheadset on that bike.
Kona Project 2 forks are quite well regarded, and cost about £50 new.

 

[Plax]

Example of A-Head stem, with this type, the stem clamps onto the top of a threadless fork steerer. The A-Head stem is the locking system that holds the headset together and the forks in the headtube. If you remove the stem, the forks will fall out and the headset will come apart.
http://www.chainreactioncycles.com/Models.aspx?ModelID=6286

Example of quill stem, stem is inserted inside the steerer tube, this is used with a threaded fork steerer, you can remove a quill stem without the forks or headset all coming apart.
http://www.raleigh.co.uk/p_details.aspx?id=2554

The two e-bay links you have shown are both for quill stems as the fork steerer is threaded.

Have a look and workout if you need a threaded or non threaded fork steerer. When you replace the fork, you need to check that the fork steerer on the new fork is long enough, before buying the forks, if it's too long, you can easily cut it down with a hacksaw. If you need threaded fork steerer, make sure the thread comes down far enough.

HTH

Cheers for that Giles, looks like I have an ahead stem then.

IIRC you've got an Aheadset on that bike.
Kona Project 2 forks are quite well regarded, and cost about £50 new.

Ah, but are they black? I need black forks or the colour scheme will look a bit naff

 

[Landslide]

Does Plax also need to check the length of them?

Aye, ideally you'll want the same crown race to axle measurement on your replacement forks (allowing for initial sag when measuring the suspension forks).

 

[Plax]

Aye, ideally you'll want the same crown race to axle measurement on your replacement forks (allowing for initial sag when measuring the suspension forks).

So would I need to take the fork off to measure the steerer length or could I measure from the top of the stem and to the bottom of the front tube thing (can't remember what the technical term is!).

 

[e-rider]

I've not read all this thread BUT if you are changing your forks you NEED to get the same axle to crown length or just about the same.

The steerer NEEDS to be the same diameter (eg 1 1/8")

AND the steerer tube NEEDS to be long enough.

So, lets say you have seen some 1 1/8" rigid forks, and the steerer is new and uncut (easily long enough for your frame size).

2 things you must worry about:

1. the axle to crown length is the same as your existing forks
2. you will need to trim down the steerer tube (but not too much as there's no going back!)

If you have 100mm travel forks the AtoC length is going to be in the region of 445mm but check this accurately first. Forks with a AtoC of 440mm to 445mm should be fine.

 

[Landslide]

So would I need to take the fork off to measure the steerer length or could I measure from the top of the stem and to the bottom of the front tube thing (can't remember what the technical term is!).

That's not what I was referring to.

Sit on the bike so your suspension compresses to its usual ride height.
No get Mr Plax to measure the distance from the bottom of the crown race (lower part of the headset bearing assembly) to the axle of the wheel.
Any replacement (rigid) fork should be similar to this length. If it is any shorter, the head angle of your frame will become steeper, and the steering will become more "lively". If the replacement fork s longer, your head angle slackens with the steering feeling more "laid-back".

As for steerer tube length, don't worry about taking the fork off the bike, just measure from the crown race again, but to the top cap where your stem bolts onto the steerer. As long as your replacement fork's steerer is at least this length you'll be OK. You can always trim a too long steerer.

 

[Plax]

Okay I'm having problems.
I've got some second hand Kona P2 forks. Already has a star nut and lower race.
Fitted the forks to the bike, but there is some play in them, feels like a bit of "side to side" movement in the lower crown area if you follow me. Any ideas what I could have done wrong based on this naff descrition I've just given you?

 

[Plax]

Does the crown race on the P2s match that of the old fork? If they're not identical, that's your problem.

If the two are the same, then it might just not be tight enough.

Thanks User,
They look the same with the naked eye, but I shall look in more detail later. Otherwise it'll be a b*tch to try and get them both off and swap them over! Don't suppose there is an easier way other than to take to the LBS who have the proper tools.

 

[Plax]

I couldn't get the lower crown race off my old forks, so I took it into the LBS and they did it for me. There was a lower crown race on the rigid forks, but it was the wrong one for my bike. Haven't been for a proper ride on it yet, but it seems spot on and a somewhat lighter than with the old forks.
Thanks for all the help

 

[fossyant]

Nice one - headset's/crowns/races aren't usually compatible unless the same model.