Fork length...

A friend of mine wants to start commuting to work - she's got an old mtb which is in good working order, apart from the suspension forks, which are basically dead. So, I suggested just putting some rigid forks on it as it's all on roads anyway. However, after getting my revolution courier last week, I realised that not having a suspension fork seems to lower the front end of the bike a hell of a lot - even though the frames are the same size, the saddle to bar drop is way higher on the courier. Now, said friend does have back issues and is also on the more rotund end of the spectrum, so likes to sit upright.

So, to finally get round to my question - do all rigid mtb forks have the same length legs, or is there some variation? I know the length of the steerer tube can vary, but what about the actual fork legs? Sorry if that's a really stupid question... Also, can anybody suggest a cheap fork?
 

battered

Guru
Alternative get out of jail free card - fill the shot forks with thick oil instead of whatever is in there now (probably nothing). I suggest gear oil for cars. It costs very little and it *might* get you running, albeit with suspension that doesn't really suspend anything.
 
OP
punkypossum

punkypossum

Donut Devil
Don't think she is adventurous.... riding a bike is adventurous for her!!! Just had a google for suspension corrected forks tho, they all seem to be about 200 quid - she might as well get a new bike for that!
 
Dead how? Seized or sloppy? If seized leave them on there. The cost of replacing them with an after-market fork might easily exceed the value of the bike.

An increase of one inch on the fork height will change the head tube angle by one degree, and (depending on the amount of offset or fork rake) this can seriously upset the steering.

Fork length is measured from the centre of the drop-out to the bottom of the crown race.

An 80mm travel fork will require an '80mm suspension adjusted' rigid fork and so on.

Cheap fork? A few years ago every bike shop had a pile of surplus rigid forks under the workbench.
 
OP
punkypossum

punkypossum

Donut Devil
mickle said:
Dead how? Seized or sloppy? If seized leave them on there
Definitely not seized, it's hard to describe, they sort of just clonk up and down, i.e. if you lift the bike's front end off the floor, the fork just falls down to fully extended, if you put it back down it goes all the way back in...it's very odd....
 
punkypossum said:
Definitely not seized, it's hard to describe, they sort of just clonk up and down, i.e. if you lift the bike's front end off the floor, the fork just falls down to fully extended, if you put it back down it goes all the way back in...it's very odd....
Someone has taken the internals out of them?
 

Rohloff_Brompton_Rider

Formerly just_fixed
for 200 quid she could good bike offa ebay
 

Rohloff_Brompton_Rider

Formerly just_fixed
battered said:
Alternative get out of jail free card - fill the shot forks with thick oil instead of whatever is in there now (probably nothing). I suggest gear oil for cars. It costs very little and it *might* get you running, albeit with suspension that doesn't really suspend anything.
+1. it does sound like they are empty
 

RedBike

New Member
Location
Beside the road
Yes there are different length forks.

You're intrested in the axle to crown length being about 44cm (I think) for a bike that takes 100mm forks 46cm to replace a 130mm fork
 

RedBike

New Member
Location
Beside the road
The Kona Project 2 fork used to be about ~£70 and seems to be highly recommended by most people.
The Exotic forks start from about £60.
I don't know what the aluminium exotic forks are like but I can highly recommend the carbon ones.
 

RedBike

New Member
Location
Beside the road
punkypossum said:
Definitely not seized, it's hard to describe, they sort of just clonk up and down, i.e. if you lift the bike's front end off the floor, the fork just falls down to fully extended, if you put it back down it goes all the way back in...it's very odd....
Old suspension forks used to have elastomers inside them. Think squiggy rubber block. This rubber block has probably rotted away.
 
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