Help finding the right suspension corrected rigid fork...

bluebus200

Active Member
Hi all...

I am trying to replace the terrible suntour suspension fork on my genesis latitude with a rigid fork and need some help because I am a Bit of a newby tinkerer!

So the forks that are currently on the bike have a 1-1/8 tapered steerer and 120mm travel. The wheels are 650b. The steerer tube on the bike is straight so can I use a fork with a straight steerer?

Can anyone a suspension corrected rigid steel fork?? Or at least expalin how I measure the fork to make sure I get the right replacement.

Many thanks..
 

simon.r

Person
Location
Nottingham
I’m looking at doing something similar. As a starter (I’m sure others will add info) I think you need to know the following:

Axle to crown length (with sag)
Steerer size (tapered from what to 1 1/8”?)
Steerer length
Width (enough to fit tyre in)
Type of axle (Q.R. / thru) and spacing
 

Globalti

Legendary Member
If you ask at local bike shops you might find they have some forks knocking ago I d. Otherwiselook at Carbon Components for eXotic carbon forks, there's a massive choice and I'm sure they will advise you.
 

simon.r

Person
Location
Nottingham
I was looking into this last night (for my own bike) and one other point is brake type / mount and max rotor size. A lot of carbon forks seem to have a max rotor size of 160mm.
 

Globalti

Legendary Member
That'll be because a bigger rotor stresses the fork so much that it would need to be much heavier and as thick as a suspension fork.
 
OP
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bluebus200

Active Member
Thanks all...so I waiting for some calipers to make proper measurements but in the mean time what I am wondering is can I use a fork with a 1-1/8 steerer? The original fork is 1-1/8 at the top tapered at the bottom and the tube on the bike is straight...is it not a matter of fitting the right headset to hold a straight steerer??

Ps I am looking for steel forks only...
 

Globalti

Legendary Member
Why does a bigger rotor (how big) stress the fork more? If you can endover with a 160 then that's peak moment, no?
Just asking.
More leverage where the caliper is attached to the fork?
 
OP
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bluebus200

Active Member
I’m looking at doing something similar. As a starter (I’m sure others will add info) I think you need to know the following:

Axle to crown length (with sag)
Steerer size (tapered from what to 1 1/8”?)
Steerer length
Width (enough to fit tyre in)
Type of axle (Q.R. / thru) and spacing
have you looked at the surly karate monkey?
 

figbat

Slippery scientist
More leverage where the caliper is attached to the fork?
I've been trying to visualise this myself. The caliper mount is always in the same place on the fork. As @Ajax Bay said, if a 160mm disc can create enough turning moment to lift the rear wheel then a bigger disc can only do the same thing, perhaps with less braking input at the lever. A bigger disc gives a longer (but faster-moving) braking track and greater retarding moment for a given pad-to-disc friction.

My only thought is that if you run a bigger disc you can more easily brake harder so you may find yourself doing more hard braking, meaning the overall peak forces won't be any different, but the average applied braking forces will be higher. Or something.
 
OP
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bluebus200

Active Member
I've been trying to visualise this myself. The caliper mount is always in the same place on the fork. As @Ajax Bay said, if a 160mm disc can create enough turning moment to lift the rear wheel then a bigger disc can only do the same thing, perhaps with less braking input at the lever. A bigger disc gives a longer (but faster-moving) braking track and greater retarding moment for a given pad-to-disc friction.

My only thought is that if you run a bigger disc you can more easily brake harder so you may find yourself doing more hard braking, meaning the overall peak forces won't be any different, but the average applied braking forces will be higher. Or something.
[/QUOTE

Fascinating but (no offence intended) there any chance of staying on topic? The question is pretty specific lol.
 

Jody

Veteran
Thanks all...so I waiting for some calipers to make proper measurements but in the mean time what I am wondering is can I use a fork with a 1-1/8 steerer? The original fork is 1-1/8 at the top tapered at the bottom and the tube on the bike is straight...is it not a matter of fitting the right headset to hold a straight steerer??

Ps I am looking for steel forks only...
Is the frame tapered or straight? If straight then you can't use a tapered fork (unless it's over 1-1/4) but if tapered you can use a straight fork given the correct headset and stearer size. At the top you said the frame was tapered.

As for steel forks only, you can get carbon for rock bottom prices these days so I wouldn't rule it out unless there is a specific reason you want steel.

To add on to @simon.r post you also need to know the offset of the suspension forks you are replacing.
 
OP
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bluebus200

Active Member
Is the frame tapered or straight? If straight then you can't use a tapered fork (unless it's over 1-1/4) but if tapered you can use a straight fork given the correct headset and stearer size. At the top you said the frame was tapered.

As for steel forks only, you can get carbon for rock bottom prices these days so I wouldn't rule it out unless there is a specific reason you want steel.

To add on to @simon.r post you also need to know the offset of the suspension forks you are replacing.
Thanks... So the the frame is straight but the fork is tapered to 1-1/8.
By off set you mean the angle from the crown to the axle?

I have been looking at the surly karate monkey...https://www.modernbike.com/surly-karate-monkey--fork---27.5-110x15mm-thru-axle-1-1-8-straight-steerer-steel-toxic-tangerine
518355

518356


518357
 

Ajax Bay

Veteran
Location
East Devon
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