Forks question

apple eater

Yet another "needs to be put right bit" on my recent acquisition.

The forks are travelling down the their maximum and staying there when riding but return when i get off. I've maxxed the pressure on the top adjuster but this makes no difference.

Also the lockout tab has broken off, can i get a replacement tab?

The forks are suntour XCM.

I know not the best but this is a cheap quick replacement bike for my son tha has to do for now.

Thanks

Greer_

Pressure? They're coil, so I take it you mean the preload? It rarely makes much difference. (what is your question about them?) The forks are poor (I had them myself) but are better than others in the same price range and they're easy enough to service. Just slide off the lowers using the nuts at the bottom of each leg, clean and regrease, and put them back together. Ask me for a bit more detail if you need it Your LBS may be able to source a lockout lever, I'm not sure if anywhere does them online.

The Rookie

Could be the lockout, you don't need the lever to rotate it, pliers (gently) will do it, or it could just be the fork bushings (the seals are rubbish).

Lower level Suntour are well worth a clean/lube, easy to do...
Loosen bolts on bottom of stanchion (2-3 turns), tap with a hammer to push the bolt heads up and loosen location of uppers in lower.
Undo and remove those bolts, pull upper from lower.
Clean out all the crud from both uppers and lowers, remove as much as you can.
Fresh grease (not too much) on the bushes (plastic bits at the top of the lowers)
Push uppers back into lowers (THE RIGHT WAY ROUND)
put bolts back in and do up.

Voila, one knackered set of forks back to no worse than when new.

apple eater

I understand fully the clean and rebuild aspect to the forks. Are these forks just spring dampened or is there oil in there too?

I don't think there is, it just doesn't appear that way. with regard to the seals are these seals standard and if so are the better aftermarket replacements. I am of a fairly low opinion of the suntours as i have them on my bike and they are too soft and a bit on the heavy side.

mrmonkfinger

apple eater wrote:

I understand fully the clean and rebuild aspect to the forks. Are these forks just spring dampened or is there oil in there too?

Damping is seperate to the spring, it will be oil. May well be a sealed oil damper unit in one leg, and spring in the other leg.

nicklouse

have you downloaded the service manual from suntors web site yet?

many forks do not have any form of liquid damping and those that dont often dont have anything pretending to do any damping at all.

The Rookie

Suntour XCM can have a sealed cartridge damper or not depending on the exact year/model, as its sealed, there is no need to worry about it if it does!

1mancity2

The Beginner wrote:

Suntour XCM can have a sealed cartridge damper or not depending on the exact year/model, as its sealed, there is no need to worry about it if it does!

If the cartridge is broken that could be the problem, you can modify them into an open bath system if its a suntour nitrogen model.

apple eater

I've stripped cleaned and refitted the forks this evening. One leg was a concealed spring which was very strong and good resistance. The other leg was a nitrogen tube which although it seemed to operate ok i think it was a bit weak.

This tube was connected to the manual lock out (which was missing) and so always unlocked.

Can i remove this nitrogen damper and replace with the same concealed spring unit as in the other leg and if so is there somewhere that can supply me with this? I'm not bothered about the lockout as it's being used cross country only.

supersonic

You could get a new pushrod and spring, but the cost would be similar to a new budget fork. And with no damping will perform worse.

apple eater

What about a new or uprated damper? Are they standard sizes but different makes?

supersonic

There are no damper upgrades for this fork unfortunately.

I consider buying this:

http://www.ebay.co.uk/itm/2011-Suntour- ... 43acdf7ad9

Probably cheaper than what you plan to do with new internals. Good fork, nicely damped, and a good pound lighter than the XCM.

apple eater

Thanks for all the quality replies.

now i'm looking for new forks, what do i need to take into account?

I know the following

tube size and the neck length
fork travel (100mm)
condition new used or abused.

What other conditions/variations should i be aware of?

Greer_

- Crown/axel length but doubt it will matter too much geometry wise
- You'll want a QR fork, unless you're planning on changing hubs/wheels

- whats your budget? Maybe rebas or recon gold (both air for more adjustability) or recon silver which is just a budget coil fork

apple eater

Ok i left out one vital piece of info, max budget 100 gbp.

Greer_

I don't know if there's much point upgrading at that price, it wont be much better than what you currently have i.e. for£110 you can get a recon silver - http://www.on-one.co.uk/i/q/FORSRETK-BL ... mm___1_1_8

But it really is worth saving up an extra bit for either http://www.on-one.co.uk/i/q/FORSRECGLDA ... isc_and_vs
or http://www.on-one.co.uk/i/q/FORSRERL-BL ... qr___1_1_8

The Rookie

The XCR is a reasonable upgrade on a budget as linked to by SS, it has damping and better seals.

The 'tube' is called a steerer when you look in adverts by the way!

Good used from ebay/classifieds may be a better option? As long as you have the skills (basic DIY) to fit it yourself!

apple eater

fitting is no problem. these forks are definitely much worse than as new. My suntour forks work excellently but when i get on my sons they just drop and don't return unless i whip them up with a pull on the bars.