100mm front forks to 120mm

swod1
swod1 Posts: 1,639
edited July 2013 in MTB buying advice
I've had my bike for a year now and looking at a fork upgrade as basically the suntour forks are terrible, was fine for general riding around which i was doing at the time to get better fitness.

I ride alot off road now and the suntours just dont cut it on local trails and woods seem rather stiff.

the deals on forks seems to be better on 120mm rebas etc and would changing from 100mm travel to 120mm make a drastic change to the bikes handling ?

bike is a trek 4500 with 100mm travel suntour xcm forks.

I can spend a fair bit to get some rebas or those SID's on On one site but i see most of them on offer come with push or poploc remotes which i'm not bothered for.

anything else i should consider ?

Comments

  • mcnultycop
    mcnultycop Posts: 2,143
    You need to make sure it won't invalidate your frame warranty; some Rebas can be reduced in travel with spacers supplied with the forks in any case.
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  • swod1
    swod1 Posts: 1,639
    mcnultycop wrote:
    You need to make sure it won't invalidate your frame warranty; some Rebas can be reduced in travel with spacers supplied with the forks in any case.

    I dont think i will have one as i've had the bike over a year now and forgot to register it with trek oops.

    I do like these for the bike _http://www.on-one.co.uk/i/q/FORSRRL100/rockshox_reba_rl_solo_air_100mm_fork

    Pop loc compatible, does that mean it has the turnkey on the fork for lockout ?
  • .blitz
    .blitz Posts: 6,197
    swod1 wrote:
    ...would changing from 100mm travel to 120mm make a drastic change to the bikes handling ?
    I used to have 130mm Toras on my old Chucker they made quite a difference. The front end was higher, the bb was higher and effectively the seat tube angle was slacker so it made it a bit more difficult to pedal. It also had a tendency to flop over on tight uphill switchbacks. I ran the forks deeper into their travel to try and get the geometry back but it was never right.
  • The Rookie
    The Rookie Posts: 27,812
    Looking at a 4500 frame, I don't think I'd go to 120's but stick with something that could be used as 100's.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • swod1
    swod1 Posts: 1,639
    The Beginner wrote:
    Looking at a 4500 frame, I don't think I'd go to 120's but stick with something that could be used as 100's.

    Probably best I stick with getting some 100mm rebas or sid's then.

    Better forks will improve the ride I hope, these suntour front forks I can feel it right up to the bars even the littlest bump the forks don't compress enough/feel hard
  • The Rookie
    The Rookie Posts: 27,812
    A straight service can make a huge difference to Suntour XCM's......
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • swod1
    swod1 Posts: 1,639
    The Beginner wrote:
    A straight service can make a huge difference to Suntour XCM's......

    maybe but to be honest they are a pile of rubbish and i want to change them, was fine for the use at the time of getting the bike.

    Going back to this i've seen some really good deals on forks especially rebas and looking to buy some now.

    Do i get them in white or stick to black to match the frame as i know you guys like your colour schemes.

    i need some advice too, seen some really good priced rebas but are tapered 1.5 to 1 1/8 inch, the head tube on my trek looks about 1.5inch with a reducer fsa headset thats been on it since new.
  • The Rookie
    The Rookie Posts: 27,812
    Most likely a semi integrated for 1 1/8th....you'll have to take it off and find out!
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • swod1
    swod1 Posts: 1,639
    The Beginner wrote:
    Most likely a semi integrated for 1 1/8th....you'll have to take it off and find out!

    I have had a look when i needed to tigthen it up a while back and the bearings are pressed into the frame.

    I could just buy the rebas in white 1,1/8th steerer size as the price of them is too good on various sites.
  • felix.london
    felix.london Posts: 4,067
    120mm could be OK. Measure your axle-to-crown height.

    If you have a 1.5" headtube and you get a set of 1 1/8" forks you'll be able to lose at least 10mm of the A2C height by fitting a zero-stack/internal lower-cup headset.
    "Why have that extra tooth if you're not using it?" - Brian Lopes

    Votec V.SX Enduro 'Alpine Thug' 2012/2013 build

    Trek Session 8
  • cooldad
    cooldad Posts: 32,599
    I am pretty sure a Trek 4500 with XCM's doesn't have a 1.5" headtube.
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  • felix.london
    felix.london Posts: 4,067
    cooldad wrote:
    I am pretty sure a Trek 4500 with XCM's doesn't have a 1.5" headtube.

    of course it does...
    swod1 wrote:
    the head tube on my trek looks about 1.5inch
    "Why have that extra tooth if you're not using it?" - Brian Lopes

    Votec V.SX Enduro 'Alpine Thug' 2012/2013 build

    Trek Session 8
  • The Rookie
    The Rookie Posts: 27,812
    swod1 wrote:
    The Beginner wrote:
    Most likely a semi integrated for 1 1/8th....you'll have to take it off and find out!

    I have had a look when i needed to tigthen it up a while back and the bearings are pressed into the frame.
    And many semi intergrated are pressed direct into the frame.

    2011 Trek 4500 with XCM's and an semi-integrated
    http://www.evanscycles.com/products/tre ... 3#features
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • swod1
    swod1 Posts: 1,639
    The Beginner wrote:
    swod1 wrote:
    The Beginner wrote:
    Most likely a semi integrated for 1 1/8th....you'll have to take it off and find out!

    I have had a look when i needed to tigthen it up a while back and the bearings are pressed into the frame.
    And many semi intergrated are pressed direct into the frame.

    2011 Trek 4500 with XCM's and an semi-integrated
    http://www.evanscycles.com/products/tre ... 3#features

    Its the 2012 model.

    I maybe mistaken but once bearings are pressed into the frame the size lowers to 1 1/8th for the steerer tube ?

    another decision black frame and white forks ? seems diffusion black is sold out.
  • The Rookie
    The Rookie Posts: 27,812
    The seat diameter for semi integrated is 44mm, the ID of the tube between the 2 seats could be anything upto 40mm, some will take a 1.5" (aka 38mm) steerer and some won't, but you'd need a new external headset. Or just stick with a 1 1/8th steerer.

    Yes, the ID of the bearings is a little over 1 1/8th and the crown race/compression ring take up the difference.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • swod1
    swod1 Posts: 1,639
    The Beginner wrote:
    The seat diameter for semi integrated is 44mm, the ID of the tube between the 2 seats could be anything upto 40mm, some will take a 1.5" (aka 38mm) steerer and some won't, but you'd need a new external headset. Or just stick with a 1 1/8th steerer.

    Yes, the ID of the bearings is a little over 1 1/8th and the crown race/compression ring take up the difference.

    looking tonight at the bike and it looks to be correct what you said and not 1.5inch.

    I will stick to 1 1/8th steerer size to be sure of new forks fitting.
    felix.london wrote:
    120mm could be OK. Measure your axle-to-crown height.

    this is 49.5cm

    thank you for your comments so far.
  • felix.london
    felix.london Posts: 4,067
    swod1 wrote:
    felix.london wrote:
    120mm could be OK. Measure your axle-to-crown height.

    this is 49.5cm

    thank you for your comments so far.

    Double check but a 120mm Reba's A2C will not be too much more than that I should think. You can also 'suck' some of the available travel down using the neg. air chamber (I have 110mm of available travel on mine which seems to gives me a super smooth ride)
    "Why have that extra tooth if you're not using it?" - Brian Lopes

    Votec V.SX Enduro 'Alpine Thug' 2012/2013 build

    Trek Session 8
  • swod1
    swod1 Posts: 1,639
    thanks for all your help and advice.

    I have bought some 100mm rockshox rebas and should have them next week.

    I now will need to buy a shock pump, any recommendations or will any do ?
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    If you bought proper aftermarket ones then they should come with a pump.

    Otherwise many are the same, just rebranded. Beto halfords ect. I wouldn't spend more than £20 though.

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