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Track Cycling: Velodrome Racing and Training Area Looking to enter into the realm of track racing? Want to share your experiences and tactics for riding on a velodrome? The Track Cycling forums is for you! Come in and discuss training/racing, equipment, and current track cycling events.

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Old 03-19-13, 07:36 PM   #1
kayp
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fork rake question-

About 3 years ago, as a fixed gear kid, I bought and built up a Dolan Precursa. I opted for the road fork option because I was running a front brake. Well it has been sitting around since then and now that I have gotten more into road racing I figured I could put my Dolan on the track with a few modifications. Basically, will the road fork be a problem for at least a few races before deciding on my track racing future or is it a definite no?
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Old 03-19-13, 07:50 PM   #2
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What track will you be at?
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Old 03-19-13, 07:59 PM   #3
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What track will you be at?
Trexelertown- 333m, 28degree bank, concrete
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Old 03-19-13, 08:03 PM   #4
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It depends on the head tube angle of your frame, and the rake of the "road" fork they sent you. Look those up and post 'em here so that we can tell you that no, it won't be a problem for your first races.
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Old 03-19-13, 08:06 PM   #5
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It depends on the head tube angle of your frame, and the rake of the "road" fork they sent you. Look those up and post 'em here so that we can tell you that no, it won't be a problem for your first races.
43mm fork rake and head angle is 73
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Old 03-19-13, 09:02 PM   #6
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For your first 3-4 years it will never be an issue. It MAY become an issue when you get to a Cat 1-2 level.
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Old 03-19-13, 10:23 PM   #7
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I raced the entire season last year at the Dick Lane Velodrome on a road fork with no issues. I even made it up to the velodrome in Rock Hill, South Carolina one weekend and had no issues on their much shorter/steeper track.
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Old 03-20-13, 06:19 AM   #8
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73/43 comes to a trail of 5.9, which is perfectly reasonable for track bikes.
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Old 03-20-13, 08:15 AM   #9
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Is there any place I can read about trail and how it affects track bike handling? Also, how is trail calculated with the HT angle/rake?
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Old 03-20-13, 11:20 AM   #10
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Is there any place I can read about trail and how it affects track bike handling? Also, how is trail calculated with the HT angle/rake?
Two excellent places to start are ex-framebuilder Dave Moulton's blog articles, Head Angles and Steering and Trail, fork rake, and a little bit of history.

The formulas for determining trail for a given fork rake and for determining fork rake to get a given trail are:



It's easiest to use a scientific calculator with trig functions, but if you don't want to mess with the math use the on-line version of BikeCAD. You can play around with different wheel (rim and tire) sizes, head tube angles, and fork rakes to see what trail the different combinations will produce.

Examples:

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Old 03-20-13, 05:11 PM   #11
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Don Walker's The Truth About Track Bike Geometry is good, too.
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Old 03-20-13, 06:24 PM   #12
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Don Walker's The Truth About Track Bike Geometry is good, too.
Excellent. Thanks for the link.
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Old 03-20-13, 07:15 PM   #13
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Probably not a problem on that track, but I put a road fork on a bike once (increasing offset by 5mm) and it made the bike pretty squirrly on a short steep track. Worked fine on there road, probably made the bike more responsive, but was a handful on the short track. Mild 333m track, probably OK (assuming it rode fine on the road). But if you take up the sport, get the bike back to spec as soon as you can.
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Old 03-21-13, 11:44 AM   #14
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One more thing:

road forks are not designed to take the extreme side loading you get on a track. People around here pull 3-4G's on a track while moving up/down track, and good ones can sprint out of the saddle at those G forces. Probably not an immediate concern for you on a 28 degree track, but something to keep in mind for the long term.
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