Suspension Forks Problem

thefootster

Hi folks,

I've had a word about this on here before, however, the plot has now thickened!

I took my bike into a very highly recommended shop the other day to get some suspension forks fitted (it's a rigid just now).

Anyway, the lad in the shop said that because of the elevation increase when adding suspension forks, it would knock the Geometry of the bike out too much, therefore, would be a bad idea!

Has anyone got any ideas/info on this?

Has anyone converted a rigid MTB to suspension before?

My bike is really lightweight model made by Sunn who apparently don't do mountain bikes any more, however, they are (or were) apparently really good bikes.

I would really like to keep it rather than get rid of it & fork out a wedge on a new one, as a new one of a simiar weight is going to cost me a small fortune, but it is definitely in need of some modifications!

danhargrave7

what size wheels are you running? and it shoudnt be to bad, but im no boffin on this stuf, just saying that anything over 100mm travel will definately be to much.
how much clearance is there between the top of your front wheel, and the underside of the crown of the forks atm?

dan

If practise makes perfect... And nobodys perfect... Then why practise...? Because Its so amizingly fun!?!?! YES!!!

nicklouse

if the bike is not designed for sus then yes it will destroy the ride.

Sunn are still making bikes.

for every 24.5mm increase in the axel to crown race the head angle will change by 1 degree.

finally light weight in '99 is average now.

nick
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thefootster

Fair one!

I've got 26in wheels & the clearance id aprox 1 - 1.5in from the forks.

On the point of the 99 lightweight / average thing, what kind of price would I be looking at paying for a similar weighted, good allrounder, bike with decent suspension? I really dont want to go any heavier and enjoy the fact that I can vary my riding on it, ie I like taking it up to the lakes for the odd day, or doing up hill training & occasionally end up on the odd road.

Stinkyboy

have a look at some 80mm pace forks they'd go nice, rigids tent to have a steep head angle anyway so a little bit of slack wont do too much damage, especialy if you keep it short travel

HUDDERSFIELD DH SCENE

nicklouse

so what is the cuurent weight?

nick
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thefootster

I'm not sure what the exact weight of it is, however, I've been comparing it to the average ones in the shops from halfords to winstanleys, and even the the MTB shop at Grizedale & it's much lighter than most of them (except some of the really pricey ones!!!).

I will try to find out & will put the details on later.

Meanwhile, here are the pics of it, as you can see, it's completely standard as far as I can gather. I only really got into mountainbiking when I was 'out of the game' for a while after a bumpy skydiving accident a couple of years ago. It kept me going whilst I couldn't run. I quite liked the sport anyway & am keen to get into a bit more.

http://www.pinkbike.com/photo/?op=list& ... rid=156118

nicklouse

nice and clean. you might get a way with a 80mm fork but less would be better.

but it looks like your cranks are bent!

nick
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thefootster

It aint that clean just now mate, believe me!!! HA!

Cranks - bent? would you mind ellaborating a bit on that Nick? I'm not really up to speed on the techy stuff.

My main aim is to do a lot of upgrades to it - but only if I can sort the suspension thing out. It skips the gears every now & then, would that be a problem caused by the cranks? The gears are actually next on the agenda if I do get the suspension sorted.

nicklouse

they do not seem to be at 180 degrees in the pictures.

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thefootster

Must just be the picture Nick - it rides fine. It's been serviced since the photos anyway.

ROCHA

http://insidesunn.canalblog.com/images/IMG_8996.JPG
Sunn tox Same frame as yours, isnt it?
http://insidesunn.canalblog.com/archive ... index.html
This one has a 40mm Obsys Chaos suspension fork made by SUNN, but probably not stock specification 'cause that fork was being used by world cup event winners at the time in much more expensive Sunn bikes.
Your bike, in its original specifications, was indeed light! Especially if you consider it's price. It was around the price of a spesh hardrock and it weighed 11.4kg with a rigid fork! Not bad at all!


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thefootster

Nice one Rocha! - been trying to find some info on it for ages now! Wot do u rekon it'd be worth now mate? - Might have to put it on ebay & put what I get for it towards one with suspension (as it sounds almost impossible that I'm gonna be able to get it upgraded!)

Anonymous

I would reckon 100mm fork on that thing as an absolute maximum. I personally don't mind ultra relaxed head angles, but 100mm would loosen up your steering considerably, to the point that most people wouldn't like it.

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ROCHA

How much would you get if you sold a '98 spesh hardrock frame? That's about the same you'd get for yours. Your frame will take a 80mm fork and you'll still have a good XC/AM bike. If you're planning to have more travel forget about it.

WD-40? GT-85?? I'd rather use the old AK-47!

thefootster

Thanks Rocha - sound advice! I have no idea how much a 98 Spesh would be (& in my very limited MTB knowledge, have never even heard of one), but I'll have a look for some 80mm forks in that case!!! - Any particular make you could recommend? I'd like to keep it light so as not to set the bike off balance or make it top heavy.

ROCHA

Magura Odur
http://www.chainreactioncycles.com/Mode ... elID=16511
Marzocchi MX pro
http://www.chainreactioncycles.com/Mode ... elID=13462
Those two are reliable and not expensive,
but if you want it lighter and not as sturdy:
Rock shox SID
http://www.chainreactioncycles.com/Mode ... delID=8726

WD-40? GT-85?? I'd rather use the old AK-47!