Fitting 160mm forks...
 

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Fitting 160mm forks on a hardtail frame designed around 130mm forks

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So i have two sets of forks, one is 130mm of travel with a 42mm offset and the hardtail frame they are on is designed around that amount of travel and offset

I also have a set of 160mm forks with 44mm offset, these are just sitting around not being used but are back up for my 160mm travel bike

Both sets of forks are different makes but have the same amount of adjustment, spec level etc...

I was thinking about fitting the 160mm forks to the hardtail frame designed around a 130mm fork

Now adding 30mm more travel to a hardtail frame designed around 130mm of travel would change a few things and may affect the ride/handling

I lined up the 160mm forks alongside the 130mm forks expecting them to be 30mm longer but they are not? the bottom of both forks and the top match perfectly

The 160mm forks have a 30mm shorter lowers than the 130mm fork

So am i missing something here? or will the 160mm forks work fine on a hardtail frame designed around 130mm forks


 
Posted : 26/08/2022 11:33 am
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Try it. See how it feels. If you crash and die though could I have the other forks?


 
Posted : 26/08/2022 11:36 am
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I do have an itch to try fitting a silly pair of forks to my Gravel bike to see what happens there but none of my riding buddies will lend me a set of 29er forks to try it and my MTB is 650b


 
Posted : 26/08/2022 11:37 am
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I lined up the 160mm forks alongside the 130mm forks expecting them to be 30mm longer but they are not? the bottom of both forks and the top match perfectly

The 160mm forks have a 30mm shorter lowers than the 130mm fork

Is one a 27.5 set and the other a 29?

It's the axle to crown measurements you need to check, might be worth googling the specs and going from there.


 
Posted : 26/08/2022 11:41 am
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^ this


 
Posted : 26/08/2022 11:46 am
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Both forks are 29er's

One is Rockshox the other is FOX

Axle to crown measurements are pretty much the same


 
Posted : 26/08/2022 11:49 am
 5lab
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I've had long-forked hardtails before and I'm not a huge fan. The nice slack head angle you have when pootling along gets really steep when you need the slackness most - a 160mm hardtail with a 65deg static head angle will be more like 67degrees sagged and 73degrees at full travel. its managable, but a stiffer, shorter fork with the right geo is much better imo.


 
Posted : 26/08/2022 11:49 am
 mert
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So am i missing something here?

Depends how you've measured them!

But, it's not unusual to have maybe up to 20mm difference in A-C between two forks of nominally the same travel but different brands/models/duties. I had some forks BITD that were 110mm travel and only about 10mm longer A-C than the 80mm fork's i took off...


 
Posted : 26/08/2022 11:53 am
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If they are exactly the same axle to crown, once you have sagged the 160mm fork you will end up with a steeper head angle...


 
Posted : 26/08/2022 12:14 pm
 mert
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have the included negative travel in the total on the longer fork?
Is the longer fork sucked down?


 
Posted : 26/08/2022 12:52 pm
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120mm is optimum for a hard tail, 130mm at max is my limit.


 
Posted : 26/08/2022 12:54 pm
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Try it and see. It's the only way to know how it will ride.


 
Posted : 26/08/2022 12:54 pm
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What hardtail frame is it / what’s the geometry?

For me I think 160mm on any hardtail is too much - the change in geometry from fully extended to fully compressed is huge. But it comes down to personal preference at the end of the day - plenty of people are happy and love their long forked hardcore hardtails - although most of them are probably running them on bikes adjusted for that amount of travel.

Doesn’t cost you anything to try it (other then time) so give it a go and see what you think!


 
Posted : 26/08/2022 1:12 pm
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Hardtail is a Sonder Signal ST

Longer fork isnt sucked down, the visible sanctions on both forks measure 130mm and 160mm respectivly

The FOX 36 lowers measure 30mm less than the Pikes

Have fitted the FOX 36's and will test them out tomorrow

Dont use the hardtail too often so not sure if i will be able to tell much difference but will see what happens

Pic with Pikes

https://flic.kr/p/2mbkF26

Pic with 36's

https://flic.kr/p/2nGyXZ6

Had to remove 20mm of spacers from under the headset due to the slightly shorter steerer tube and rolled the bars forward a little bit


 
Posted : 26/08/2022 1:24 pm
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So am i missing something here?

Almost definitely.

Try rebalancing the positive and negative springs in the fork that’s supposed to be 160mm but is measuring same AtoC length as a 130mm fork. It could be sucked down. If it is I’ll bet it’s the Fox. Something is up anyway.


 
Posted : 26/08/2022 1:25 pm
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The FOX 36 lowers measure 30mm less than the Pikes

Get the code of the back of the fork leg and put it into Fox’s database, see what it is. Make sure it really is a 29er lower.

Overlap could be different between models/brands, so measuring seal to axle tells you nothing. Two recently made same travel pure 29er forks are unlikely to be 30mm different AtoC, I would have thought. 15mm maybe.


 
Posted : 26/08/2022 1:27 pm
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Try it. See how it feels. If you crash and die though could I have the other forks?

Second in the qué!

It will be fine. I had a cove stiffee. I ran 105mm, 150mm then finally a u turn fork that was adjustable from 85-130.

The 150mm were totally awesome downhill and rubbish up.

I ended up running 110mm most of the time.

If you don't like the longer forks, take them back off or reduce the travel.

My hello Dave has had 160mm forks on it. It's supposed to be for a 150mm, some people are running Zeb's.

It's all just personal taste.


 
Posted : 26/08/2022 1:36 pm
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Here is the spec for the Pikes, FOX website does not show as much detail

https://flic.kr/p/2nGD91p

https://flic.kr/p/2nGEKr9


 
Posted : 26/08/2022 1:43 pm
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Sweet lordy look at that seat tube angle. Yikes.


 
Posted : 26/08/2022 2:11 pm
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Imo keep the Pikes and swap leave or swap in a 120mm air shaft if feeling to slack


 
Posted : 26/08/2022 2:12 pm
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I would at least try the 160mm. I love my 150mm Vendetta, and almost equally loved my 160mm Shan. I figure it will upset your pedalling position a little by slackening the seat tube angle, and raise the BB a little. It all depends on the bike whether those changes are entirely negative.

But I personally have no interest in ever going back to less than 150mm on a HT having seen what an absolute hoot the Vendetta is. (It climbs fantastically sell too).


 
Posted : 26/08/2022 7:44 pm
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Update time

I am writing this from beyond the grave, i died in a fiery crash whist dropping down a kerb, the 160mm forks exploded with the thought of such a drop on a frame made for 130mm forks!

In reality after doing a 40 mile ride with 2500ft of climbing using the 160mm forks i found that climbing was very slightly harder but descending was much better!

As for just pedalling along it felt fine, really didnt notice any difference from the 130mm forks


 
Posted : 28/08/2022 7:09 am
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Interesting ... Though they are cliché 36s , it's like owning a gti golf ffs.

Plus they won't be asreliable as RS over time.

Plus they are not silver 😂


 
Posted : 28/08/2022 7:14 am
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Numerous times I twinged my lower back whilst climbing using a fork too long for my frame. Downhill and street stuff was a lot better. But they're a small part of my riding.

I've gone back to the original fork (although serviced it myself and it's acting far better than new due to perceived lacking grease and oil out of the factory).

I have a couple of frames here between me and the OH that are designed for a 140-160mm fork. They demonstrate to me quite clearly that my 130mm frame shouldn't have a 160mm fork in it.


 
Posted : 28/08/2022 8:13 am

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