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Thread: grass/hard track bike, BB height and trail help

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    Default grass/hard track bike, BB height and trail help

    hi all

    i was thinking about building myself a new track bike, don't particularly like the one i have at the mo

    i did some grass track racing a couple of years ago, i quite enjoyed it

    so the question is could i build a frameset that would be suitable for both the grass and velodrome use (the london 2012 olympic park is a shade over 90 mins from mine)

    i've seen it quoted that track bottom bracket height should be 11.25" (286mm) atleast, though if i used the measurement of 290mm, so to use a 170mm crank, would that seem ok, or slightly on the high side of things ? (bb height with a 22mm tub, so to gain an extra 10mm of height when using a 32mm cross tub)

    i use a 73 degree seat tube angle on my frames, 560mm square, would a 73 degree head tube angle with a 41mm rake fork, for 60mm of trail be a little steep, or would it be more sensible to use maybe a 72.5 or 72 degree HTA with a longer rake for the same 60mm of trail, or is my trail measurement not so ideal for the style of the bicycle ?

    would rather take your guys advice now, while its still a cad file, than waste a box of tubes and lugs !

    so any advice is very well appreciated

    thanks

    nathan
    Last edited by NBC; 08-23-2013 at 07:53 PM. Reason: spelling
     

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    Default Re: grass/hard track bike, BB height and trail help

    I would think the handling dynamics between the velodome and grass track would be vast. The banking, traction, speed differences would all be a lot. Added to that will be the wide range of tire profiles. Not sure one bike will do all very well. But this is why we make our own stuff, to find out.

    BTW I was under the impression that track bike BB height (being higher then road) was only an issue with the events that had both slow and fast riding. So events like pursuit, flying K, last man out that are run at speed the whole time don't need the extra pedal clearances that sprint and Madisons need.

    Maybe the real track bike builders will chime in. Andy.
    Andy Stewart
    10%

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    Default Re: grass/hard track bike, BB height and trail help

    seems like alot of the bikes used on the grass out here are from the 70's, and plenty using more modern ones, they seem to work fine, tyre clearance being the largest issue, the last frame i used for grass was a late 70's /early 80's condor, though that was a tight fit under the fork crown !

    i never sprinted,, only standing 500m or flying 200 sometimes, but generally things like 10 mile scratch races, devil and points races, and the very occasional grass madison !

    maybe i'm nuts to think of a sort of 2 in 1 track bike, maybe a track bike with a longer fork would suffice, though the guys who've maybe done this or similar before might be able to be definitive on what works and what doesn't

    thanks

    nathan
     

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    Default Re: grass/hard track bike, BB height and trail help

    We would LOVE to have some grass track racing here.
    From the accounts I've read about the bikes are nothing special other than they run 28 mm tires esp. when conditions become rutted.
    You do not require high bottom brackets for velodrome racing unless you plan to do track stands high on the bank. Madisons, miss and out, pursuit, kilo blah blah blah (basically everything except playing cat and mouse on the high bank) are all done at speed thus you won't have any significant lean angle relative to the track surface.

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    Default Re: grass/hard track bike, BB height and trail help

    I tried to start grass/dirt track racing here in switzerland. Everybody agree it would be a nice idea but it always stop there. We are simply to few to race on the road, track and cx already.
    --
    T h o m a s

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    Default Re: grass/hard track bike, BB height and trail help

    Nathan,
    Everything I know, or really have devined, about track racing comes from Andy's comments here. That said, do I have it right that all of the racing you like is either on a flat grass track (fast and slow) or in a v'drome at speed the entire time? If that's the case wouldn't the BB height issue go away? If so I want to think you could make a satisfying dual purpose recreational bike. If not racing for King & Queen, why not give it a go maybe even with tires of similar OD & width for both venues. Just thinking out loud.
    Good luck,
    John
     

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    Default Re: grass/hard track bike, BB height and trail help

    --- "grass / dirt" pista racing!!
    please clue me in!!
    any pictures??

    ronnie
     

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    Default Re: grass/hard track bike, BB height and trail help

    -- take'n the pista out the gate & across the road, at just prior sundown, & 2 X 18 holes on the country club golf course..
    new sport -- "piss of the high rollers on a pista.."

    ronnie removed from the cc roster
     

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    Default Re: grass/hard track bike, BB height and trail help

    john,

    my stuff on a velodrome is pretty much speed all the time, so i could use a lower bb height, my cinelli has 58mm of drop which equates to 276mm of bb height, if i went from a 22mm to a 34mm tub for grass, unless i'm being super dumb, the bb height is raised by 12mm to 288mm, i guess i wouldn't need it to be any higher than that ? any thoughts ?

    i wouldn't call my racing recreational, but nor is it all that serious for me either, so it just doesn't seem logical to have 2 track bikes, plus i need a home for my dura ace tub wheels lol !

    what would one consider to be a good trail measurement for a track bicycle ?

    thanks

    nathan
     

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    Default Re: grass/hard track bike, BB height and trail help

    I've always seen regular track bikes on the grass but I guess a regular road bike would have enough clearance.
    --
    T h o m a s

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    Default Re: grass/hard track bike, BB height and trail help



    I could really get into this!
     

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    Default Re: grass/hard track bike, BB height and trail help

    Or WOW......this looks like a whole lot of "rubbin' is racin'"



    The British sure know how to have a good time on a bike.
     

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    Default Re: grass/hard track bike, BB height and trail help

    That looks awesome! I'm thinking we could do something similar on a softball field. Now I just need to find a few friends stupid enough to try it with me.
     

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    Default Re: grass/hard track bike, BB height and trail help

    Quote Originally Posted by Matthew Strongin View Post
    That looks awesome! I'm thinking we could do something similar on a softball field. Now I just need to find a few friends stupid enough to try it with me.
    I'd try it.
    There is a fun little coaching game I made up which has it's roots in a mtn. bike warm up ritual me and my pals used to do.
    The mtn bike warm up consisted of us riding in a small area and trying to force the other guys to dab. Rules were as follows:
    1. Hands must stay on the bars at all times
    2. No deliberate bike to bike contact resulting in damage unless someone goes down and than it is acceptable to run their tires over.
    That's about it, same rules for the road except we ride inside a set of cones to form a 50 foot circle. Last man standing wins. Bring cr@ppy wheels.

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    Default Re: grass/hard track bike, BB height and trail help

    Quote Originally Posted by Too Tall View Post
    same rules for the road except we ride inside a set of cones to form a 50 foot circle. Last man standing wins. Bring cr@ppy wheels.
    I've done this many times and it's a blast. Last time I ended up in an on the bike wrestling match.
     

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    Default Re: grass/hard track bike, BB height and trail help

    Quote Originally Posted by Matthew Strongin View Post
    I've done this many times and it's a blast. Last time I ended up in an on the bike wrestling match.
    Thus hands on the bars. Teaches shoulder to shoulder contact (is good) and hip contact (good) hand to bar (bad)...you get the idea. It's sort of dicey but I teach people to smack wheels and overlap too so they understand which way to lean. yuck yuck dealing with linebackers in this game is not impossible, they can't track stand ;)

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    Default Re: grass/hard track bike, BB height and trail help

    We have our juniors play "knockdown" in a field. They do really well at the regional USAC camps when they play there.
     

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    Default Re: grass/hard track bike, BB height and trail help

    for you guys over the pond, is there any grass track racing at all ?

    it's pretty fun racing, all you need is a school games field that's mowed fairly short, wooden pegs, and a couple of tins of spray paint !

    maybe the english are slightly wacky instead ? lol !

    nathan
     

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    Default Re: grass/hard track bike, BB height and trail help

    Quote Originally Posted by Too Tall View Post
    Thus hands on the bars. Teaches shoulder to shoulder contact (is good) and hip contact (good) hand to bar (bad)...you get the idea. It's sort of dicey but I teach people to smack wheels and overlap too so they understand which way to lean. yuck yuck dealing with linebackers in this game is not impossible, they can't track stand ;)
    It started with hands on the bars. We just got carried away when it came down to the last two. It's such good practice for anyone who races or rides in a group. Not overreacting when making a little contact has done wonders for keeping me upright. That includes touching wheels. I was in a crit earlier this year when I guy cut across me and put his front wheel against my foot. Neither of us overreacted and we just came through the turn without issue. I immediately thought of knockdown/footdown and how helpful it is.
     

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    Default Re: grass/hard track bike, BB height and trail help

    Something like this? Independent Fabrication Blog: Grasstrack



    IF doesn't have the geo on their blog, but I imagine they might be willing to help if you were to contact them.
     

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