Taller forks for an x5tracycle?

The steering on my x5tracycle has always been twitchy, and I have attributed that to the rake of the front forks. The xtracycle lifts the back end of the S-750 frame higher than it sits natively, so the forks are more toward vertical instead of leaning back. I'd like to replace them with something taller to get more rake out of it, but I want to do it as cheaply as makes sense.

With the old Kelly Controller this did 44mph, and the forks are the suspension for the whole bike, so they need to be strong, but this is a commuter not a downhill racer, so I don't need something esoteric. I need something wide enough to accomodate 2.5" maxxis hookworms, and a disk brake mount, and frankly the taller the better.

So I could use a primer on bike fork heights, if anyone has the time. Are triple crown forks the same height as regular forks? Are all forks the same height, or what can I look for to find a taller fork?

Thanks!
-JD

nice bike. is that a surfboard on the back?

monster said:

nice bike. is that a surfboard on the back?

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Thanks!

That board is the standard cover for an xtracycle, it is passenger seating (when footsies are installed) and helps support the tube frame on the sides.
Http://www.Xtracycle.com

I've carried 6 bags of groceries,tons of boxes, slews of beach chairs and coolers and paraphenalia, and with the old Kelly controller it did 44mph, very versatile bike.

-JD

So now I am thinking that more travel on the fork means it will be taller - I am thinking replacing the 100mm travel with 150mm will help make it less twitchy.

Alternative front/rear geometry or handling ideas...

I know of someone that is an expert rigid fork maker and charges $250 plus shipping. You could put a 3" tire or more to fit inside the new fork and run it at lower pressure for shock absorption. You would get a custom height and rake and strong rigid design with disc mount. That might take the twitch out and still smooth the ride?

You could also try running a low profile tire on the back and a high profile tire on the front... or do a 24" wheel with high or low profile tire on the rear.

You could also consider re-mounting the Xtracycle front mounting tongue under the chainstay bar with a strong cross plate above the chainstays with bolt through tongue underneath and plate above... this will rock the rear end down in relation to the front end.

I am sure that you are maxing preload on the front forks because of the increased weight transfer. I am replacing the fork on my X with the Surley 1x1 fork with disc and canti mounts. It has 45 mm of rake. Measure the axle to crown length and compare.
http://www.universalcycles.com/shopping/product_details.php?id=4122

oatnet said:

So now I am thinking that more travel on the fork means it will be taller - I am thinking replacing the 100mm travel with 150mm will help make it less twitchy.

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Yes, more travel means the fork needs to be taller.

Triple clamp forks are often adjustable in height, were as standard forks are set. One of my bikes is using a RoxShox Judy Triple, which uses a 100mm travel fork, but its a looong fork, ment to have some adjustment for various head tube heigths

Get a fork with "adjustable" travel,
I have one that is adjustable from 90mm to 125mm and run it at 125mm of travel. This will lift the front end up which is what you desire. A triple crown fork will really lift the front end up! Get one with adjustment from 125mm to 200mm and you have plenty of wiggle room to get what level you want. Love those monster downhill forks and will want to use one when I get my project Norco sorted out.

Thanks for the replies everyone!

Ah, the axle to the crown nut is the magic measurement. I defintely want to keep keep with a suspension fork, and I had been thinking about triple-crown forks but didn't know they had adjustable height - DrunkSkunk I think I'll be following your lead, and taking my first triple-crown plunge.

-JD

I listened to everyones advice, and went with a triple-crown fork. It did just what I wanted, the steering is less twitchy because the extra height changed the rake angle. It also made body position more comfortable. Not to mention, the buttery smooth ride of a top-grade fork is mighty nice too. I think it sags a little under my weight, I should probably figure out how to put the stiffest springs in there I can.

I got outbid on a few RockShox Judy as recommended by Drunkskunk. I liked the Judy (circa 1999? ) because it would let me use my regular skewer wheel, wheras most of the triple-crown forks I was seeing required a 20mm-through axle style wheel, which I had never used before and was another learning hurdle for me. I resigned myself to buying a new 20mm through-axle wheel, so I started looking at some of the newer RockShox Boxxers. I knew the $1600 world cup fork was way more than I wanted to spend, but I finally scored on a 2004 RockShox Boxxer Race, brand new, untouched, steeter tube uncut, absolutly mint, for under $250, $275 shipped. As a lucky added bonus, the '04 boxxer came in a silver that is not far off from the silver S-750 frame color. (Note: these are the same Tidalforce S-750 frames I have posted in the For-Sale section)

20mm through-axle wheels turned out to be much more expensive than I anticipated, and my LBS - who specializes in Road Bikes and usually orders things for me at cost - wasn't able to help me out. I eventually bought a Mavic wheelset on ebay, with a busted back wheel I didn't need, for a mere $86 shipped. Unfortunately, the seller was in Florida, and shipped it USPS Parcel post - it took a while.

I was impressed by the 20mm through-axle design once I saw it in person, no wonder Downhillers use them. I eagerly bolted everything together, using a Avid BB7 203mm disk brake I hadn't used yet... Only to find that the caliper was in the wrong position. Apparently, the Boxxer uses a different brake mount. I found an adaptor on jensenusa.com for $10, $17 shipped/tax.

I got the adaptor today and breathed a sigh of relief when it fit. Then I dropped the old fork, moved the botttom race for the headest to the new fork and inserted it into the headtub, bolted the bridge on top as high as it would go, and used clamps to compress the bottom bridge with the headtube upwards. A speedo and brake cable later, and it was maiden-voyage time. Like I said at the beginning, the results exceeded my expectations, so thank you to everyone who gave advice! Triple crown and 20mm through axle are the way to go, all my future ebikes will have them Total cost for the upgrade, $378.

So, below are pics of how it turned out, and I'll turn my signature on for this post so you can compare it to the old forks. I think the heavy-duty front end is a better visual balance for the xtracycle rear end, so it looks even better. In person it is an absolute beast, massive.

-JD

Thanks for the info. Isn't it great when you can fine tune your ride to your liking?

While I appreciate the handling characteristics of sport motorcycles, I've always recognized the practicality of the long travel suspensions found on dual-sports. When it comes time to take evasive action that includes plowing over a curb...

Selling the old forks?

dogman said:

Selling the old forks?

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This guy! LOL

Have you carried anyone on your xtracycle?