# Fork Upgrade



## jude3223 (10 Jun 2017)

My current fork has 80mm of travel, if i was to upgrade to 100mm would it mess up the geometry?
I have it in the large size
Thanks, Jude


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## fossyant (10 Jun 2017)

What's the fork you have now, and what are you thinking of upgrading to ?

Yes it will affect the geometry ! How much depends. If you have a basic sprung fork that's at 80mm travel, and upgrade to an air fork with adjustable sag, then you'll probably get away with it, as an air fork, you set sag to 20-30% (which is 20-30cm on a 100mm fork). Your sprung fork might not 'sag' the same.


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## jude3223 (10 Jun 2017)

fossyant said:


> What's the fork you have now, and what are you thinking of upgrading to ?
> 
> Yes it will affect the geometry ! How much depends. If you have a basic sprung fork that's at 80mm travel, and upgrade to an air fork with adjustable sag, then you'll probably get away with it, as an air fork, you set sag to 20-30% (which is 20-30cm on a 100mm fork). Your sprung fork might not 'sag' the same.


Currently i have All Terra CH-565 forks, im thinking of upgrading to RockShox 30 Gold RL Solo Air Forks


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## fossyant (10 Jun 2017)

A fair upgrade. Check how much sag you get when on the bike now. Rubber band on stanchion, and see how much it moves when you sit on the bike.

You'll probably get away with it moving from spring to air. It's not usually recommended.

You'll notice the upgrade just to air, but do bear in mind the additional maintenance.

Also double check the headset size - your GT is 1-1/18 and doesn't mention tapered, so ensure the new forks aren't tapered (usually 1-1/18 top and 1-1/4 lower bearing if tapered)

My son's SR Suntour spring 100mm forks don't sag much when you sit on the bike, but my RS Revelations are set to sag about 25%, so being 130mm they compress about 33mm. So you could get away with an air fork at 20mm more.


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## jude3223 (10 Jun 2017)

fossyant said:


> A fair upgrade. Check how much sag you get when on the bike now. Rubber band on stanchion, and see how much it moves when you sit on the bike.
> 
> You'll probably get away with it moving from spring to air. It's not usually recommended.
> 
> ...


The fork im looking at says its 1.1/8, is that the same as my gt's 1-1/18? Sorry i only started mountain biking recently


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## fossyant (10 Jun 2017)

Forks aren't cheap are they....


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## jude3223 (10 Jun 2017)

fossyant said:


> Forks aren't cheap are they....


Sorry if i had caused confusion i have edited my response


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## fossyant (10 Jun 2017)

jude3223 said:


> Sorry if i had caused confusion i has edited my response



You didn't, I was just saying it's a good upgrade. My suspension forks, rear shock and brakes cost more that the whole bike I bought. If I bought them in bits, as cheap as possible, I still would not have had a bike.


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## keithmac (10 Jun 2017)

fossyant said:


> Forks aren't cheap are they....



I can rember a workmate coming back from Leeds after spending £2000 on his down hill bike (San Andreas?) nearly 20 years ago. 

Looked in his car and there was just a frame and some forks, not even a whole bike!.


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## jude3223 (10 Jun 2017)

fossyant said:


> You didn't, I was just saying it's a good upgrade. My suspension forks, rear shock and brakes cost more that the whole bike I bought. If I bought them in bits, as cheap as possible, I still would not have had a bike.


Ok thanks for clarifying, i think im going to take the same approach as you and keep upgrading parts


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## fossyant (10 Jun 2017)

jude3223 said:


> Ok thanks for clarifying, i think im going to take the same approach as you and keep upgrading parts



I bought a Boardman FS Pro for less than £1k, and I couldn't have bought the parts.


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## fossyant (10 Jun 2017)

PS what sort of riding are you doing ?


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## jude3223 (10 Jun 2017)

fossyant said:


> PS what sort of riding are you doing ?


I just ride at my local trail in hadleigh


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## HarryTheDog (10 Jun 2017)

By local trail in hadleigh do you mean the trail centre ie ex olympic track, black runs etc?. Doable on the 80mm fork, lot easier on a full susser I am told, I just put up with my hardtail with 80mm of suspension though. If you are a member of Hadleigh MTB club there is lots of knowledge there with the coaches etc. NB there is a nice local MTB race going on at Potash woods tomorrow at 11:40 post code SS4 1PL good place to make contacts and speak to some experienced MTBers and have a go.( there will be some semi clueless people like me there as well)


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## jude3223 (10 Jun 2017)

HarryTheDog said:


> By local trail in hadleigh do you mean the trail centre ie ex olympic track, black runs etc?. Doable on the 80mm fork, lot easier on a full susser I am told, I just put up with my hardtail with 80mm of suspension though. If you are a member of Hadleigh MTB club there is lots of knowledge there with the coaches etc. NB there is a nice local MTB race going on at Potash woods tomorrow at 11:40 post code SS4 1PL good place to make contacts and speak to some experienced MTBers and have a go.( there will be some semi clueless people like me there as well)


Yeah the ex Olympic track, i have a friend in Hadleigh MTB club so i guess ill ask him about it and check it out


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## HarryTheDog (10 Jun 2017)

If you turn up I'll see you there, join the club lots of rides going on and when you buy some forks lots of places give you a discount with your membership. Sorry I can't be much help with the geometry question.


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## Crackle (10 Jun 2017)

20mm is about 1 degree of difference in the head angle, provided everything else is the same, such as sag and fork length. I think it'll probably be fine.


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## Jody (11 Jun 2017)

20mm will make very little difference to how the bike rides. It will slow the steering down a touch and make it a little bit more stable when going downhill on rough ground. If you have spacers under your stem you can swap them on top so your riding position doesn't change. Swapping to some nice air forks is always worth it. More adjustable and the ride feels so much better.


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## jude3223 (11 Jun 2017)

Thanks for all your responses. This may be another obvious question but it says the forks maximum rotor size is 180mm, does that mean it will work with everything up to 180mm? For instance will it work with my 160mm rotor


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## Jody (11 Jun 2017)

Yes provided you have the correct caliper mount. The fork limit just means it cannot withstand the force created by larger 200mm discs.


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## Nigeyy (27 Jun 2017)

Another thought: be careful buying that upgrade fork; many of them now are tapered (fork is bigger at the lower end of the steerer tube), so if you have an old 1 1/8 straight steerer tube, it will not fit. And fwiw, it is the way forks are going -I just upgraded my old old 1990's mtb last year with a Manitou R7 -I didn't have much choice for a straight steerer with QRs (at least over here) -though since I only paid about 150 quid including shipping and it's an excellent fork for me, it worked out nicely). 

Another issue is to be careful to purchase a fork for the right type of wheel you have -e.g. if you have the old style QR dropouts versus the new through axle design, you may need a new through axle hub laced up...... Again, I think you'll be getting less and less choices of QR as time goes on.

I was definitely fortunate to get my Manitou when I did for a straight steerer and QR; I don't anticipate upgrading the fork again as when I'm ready, I wonder if there will be any straight steerer/QR forks left on the market.


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## Celticdog (30 Jun 2017)

anything by rockshox not suntour!


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