Newbie in need of fork advice

[CaptainFutura]

Hi all,

I'm new to this MTB lark and not exactly flush with cash, so...

I've just picked up a cheapo Saracen Mantis - looks more or less exactly like this:

www.moredirt.co.uk/bikes/5748.jpg

Sorry - not allowed to post links yet :cry:

Anyway, on closer inspection the stock SR Suntour XCR forks are... well... history really. I was looking at replacing like with like but after a bit of reading it appears I can do better with a set of decent second hand forks.

I don't intend to use the bike for anything serious - mainly trails and paths and certainly not serious jumps/downhill etc and I gather Marzocchi Bombers seem to be the forks of choice.

But other than that (stupid question time), how do I tell/what do I measure to make sure any replacements will fit? Can anyone point me in the direction of a basic guide on fork replacement please?

I've yet to start pulling it apart, but it appears to be an Aheadset headset fitted to the bike.

Thanks

Pat

 

[Barneyballbags]

Hi Pat,

Measure the axle-to-crown height (measure up to the bottom of the headset, where the fork plugs in to the frame). This will give you a good place to start.

When choosing a replacement fork, choose one with roughly the same measurement (most people will be happy to measure this for you and let you know). That way you can be sure that the bike's handling won't be affected when you upgrade.

A taller fork will slacken the angles on your bike, making it more 'lazy' and less responsive, but more stable at speed.

A shorter fork will steepen the angles, and make the bike more lively and responsive, but also more twitchy. Personally I prefer this

You also need to measure the steerer length of the fork. To do this, you need to remove the forks and measure the length of the steerer tube from the crown to the top. Your forks have a 1.125" (inch and an eighth) unthreaded steerer too

Looking at your pic, it looks like your frame was designed around a longer travel fork, so I'd look at 120-130mm travel forks.

Hope this helps a bit. Any more q's just ask

 

[FairfaxPat]

A Fox Vanilla fork in 120mm would be a good choice. They've been around for at least 5-6 years now, so a used one should be fairly inexpensive. I used one for several years on my Fisher Cake and it worked great! It also uses a steel spring instead of air, so it is cheaper to service and rebuild. Pat

 

[CaptainFutura]

Thank you for your advice, guys. That's helped a great deal.

Have now torn the thing down and taken the right measurements I need to replace these horrible forks.

As you said, Barneyballbags, 1 1/8th Inch unthreaded steerer and it's 225mm long. I reckon these are the OE forks, though, because 1)Given what I've read about these forks, I doubt anyone would change to them.
2) The pic I posted isn't my bike, yet it has the same forks.

Current forks have about 60 mm travel, so I have a bid in on e-bay and fingers crossed.... Unfortunately Fox Vanilla forks would appear to be well out of my price range - I'm looking to replace the forks with good quality used ones with what it would cost to replace the current ones new - about £60!

One more Q (I expect there will be more when I actually get some forks), the top steering head bearings are just cage and balls and on inspection they were well greased but one appears to be missing - there's a ball-sized gap.

Would I be able to get replacement balls/ cages or is it easy to switch to cartridge type bearings? Or is that a waste of time.

 

[FairfaxPat]

The cages aren't really necessary, just get some new ball bearings, grease them up and reassemble with enough bearings to fill the cup. Pat

 

[Barneyballbags]

The cages aren't really necessary, just get some new ball bearings, grease them up and reassemble with enough bearings to fill the cup. Pat

What he said

The cages are more trouble than they're worth

 

[CaptainFutura]

Thanks again, guys. Good info

I'm used to working on motorbikes and I guess they are a lot harder on steering head bearings!

Another question: a lot of forks I'm seeing refer to a drop - usually 9mm. What is this measurement?

Apologies in advance if this is another stupid question.
:?

 

[drcarlos]

A Rockshox Tora in 80mm with V-brake mounts would be a good choice on that bike I reckon, you should be able to pick up a used one within your budget.

Carl.

 

[xizang]

Another question: a lot of forks I'm seeing refer to a drop - usually 9mm. What is this measurement?

Could be the 'sag' of a fork you're referring. Have a look at the videos in the link and it explain, sort of, how to set it and how much you need. Different riding styles use a different percentage of sag but 25% is roughly the norm.

http://www.ehow.com/video_2360928_set-f ... bikes.html


This may come in handy too:

http://www.tftunedshox.com/Manuals.aspx

 

[rich_4130]

Another question: a lot of forks I'm seeing refer to a drop - usually 9mm. What is this measurement?

Do you mean drop-out? It's the part where the wheel fits. 9mm for standard quick release, then there's a couple of bolt-thru types - 15 & 20mm