Changing the forks on my Wisper eco.

[Mike63]

Hi...are there any difficulties in changing the fixed forks for suspension forks on my Wisper eco ?...anything I'd need to know ?

thanks....Mike

 

[Phil the drill]

Most modern replacement forks use a threadless headset to fix them to the frame. The arrangement on the Wisper looks rather like it is a threaded type, which would rather limit your choice of replacement forks, unless you wanted to change to a set of Wisper's own.
If you wanted to fit the more universal threadless variety you will need to change the headset and stem as well. It's not beyond the home mechanic to do so, but be warned it is a fairly involved job, involving careful cutting of the steering tube on your new forks and replacement of the bearing cups on the frame. Note also that one of the (relatively few) disadvantages of the threadless headset is that it has a very limited range of height adjustment available, so some care is required in the choice of handlebar stem.

I recently upgraded my oldest son's mountain bike, fitting new forks and changing from an old threaded headset to a threadless one. It was worth it for the improvement we found in the new forks.

Hope this helps, good luck

Phil

 

[Andrew harvey]

Suspension forks come in both the traditional quill stem and A head (thread less versions).
The A head set types tend to be found on mountain bikes, or on bikes that are subject to more of force, racers, BMX's .etc., whilst the quill stems are used for less demanding bikes.
Your LBS should be able to order a pair in for you, just show them the bike, I'm biased in favour of this option as I own one.
Alternatively if you can measure the diameter of the forks you can get them from the net to match your existing headset, there's different diameter steerer tubes.
If you are replacing like for like.
The cups on the frame should be reusable, the cone on the forks will have to be removed and replaced on the new forks. You'll see it at the bottom of the steerer tube, it look like a fat washer with a round grove cut into it that takes the bearing. At some point underneath it there is normally a slight cut out for lever or wedge to be inserted, you need to prize or tap it up about 1/2" before it comes free, then tap it carefully down onto the new forks.

If you decide to change the fork type you will need a new headset that should come complete with all you need except grease. Rather than cutting A headsets steerer's down, use spacers to pack the stem up. The stem should end about a quarter of an inch below the top of the stem, on A heads, to allow for tightening down as the cap has a small collar that recesses into the stem.

I'm going the other way, binning my suspension forks for a set of solid.
The problem I have had is in finding a set of cromolly forks in 26", so I'll be running 26" rear and 700c front wheels, should be interesting, mind you I've had the forks for a month or so and not got round to it yet.

 

[Mike63]

Thanks guys...this sounds like a simple job once you have done it once or twice but as a first time it could be difficult so I called at a local bike shop and he has some forks for £40 plus fitting £15.
He claims that these are as good as you'd get on a £250 mountain bike.

Seems like this might be the way to go...what do you think ?

....Mike

 

[Phil the drill]

He claims that these are as good as you'd get on a £250 mountain bike.
Seems like this might be the way to go...what do you think ?

....Mike

He's probably right.....Unfortunately the forks fitted to £250 mountain bikes are not usually up to much. A lot depends on what you expect of them, and how much punishment you are going to subject them to. Don't expect too much!

Incidentally, decent after market forks are not that easy to source in the correct sizes for bikes with threaded headsets, as this format is not favoured by aftermarket fork producers. This is due to the variations in thread length and position between different frames. It is unwise to try to cut a tread on the steerer as it is believed to weaken it. When manufactured the threads are not cut with a die on the tube but rolled on in order retain strength.

With a threadless headset you can leave the steerer tube long to allow for an increased bar height, but apart from using spacers, there is no easy way to change stem height. You can't increase it above your chosen length, and decreasing it can lead to having a nasty, ugly and downright dangerous bit of tube sticking up through the stem - so you cut it off, and then you're back to square one as far as adjustability is concerned. The knack is to ensure you get it right at the outset, in which case all will be well .

Phil