tpc forks

[sdb69z28]

What do they use for forks on those tpc 450s? Are they the stock motocross forks?

[Dirtcrasher]

Ask Jensen or Bill at TPCtrikes......

I imagine the kit they use are for certain year/model forks.

[sdb69z28]

I was concerned about the fork lengths, the motocross bikes are so much taller than the trikes. Do they cut the fork tubes down?

[MonroeMike]

Check Jensen's build thread.

http://www.3wheelerworld.com/showthread.php?121074-Building-A-TPC

[sdb69z28]

Thanks... very interesting, looks as though they put more rake on the front end to make up for the longer fork tube. Any interest in a front end like that for a tecate, 250R or a 200x?

[Dirtcrasher]

TPC put allot of years and thoughts into there trikes. They wanted them to look as well as they functioned. I'm sure Bill got the rake/handling dead on.

Jason told me forks can be cut down but it's not cheap. And only certain forks can be cut and re-threaded internally.

Tim and Snake are making great progress; They use a 250R front end, in time he may very well switch to new triples and upside down forks.

NONE of these mods are cheap if you want a full race trike, Tim has made it simple for a lower cost yet still a seemingly well deigned trike.......

[fire1]

05 -08 crf 450r is what im using for TPC

[250tecates]

fire1 sweet trike an did you have them cut down? an what for front hub an brake setup are you running. did jaysn make your triples, thanks

[fire1]

thank you ...on my r they are 2005 ktm 85 forks ,ktm 85 brake caliper and Jason makes a brake rotor adapter to put on 250r wheel hub on my 350x im using 2001 cr 500 forks..... and for TPC 2007 CRF450R forks

[jensenracing77]

everything on the TPC 450 is based off of the 2006 CRF and TRX 450. there are several years of bikes that will work. mine (not the one i just built for my cousin) has a set from a CRF250 but will be changed very soon to the 450 forks. as for lowering them.... no need to cut anything. if you seen the freestyle pictures i was doing, that was on the stock CRF 250 forks and stock TRX450 back shock. when i put the 450 forks on they will be lowered to 11 inches. (stock is 12 of travel) you can send the forks to many suspension companies. they don't cut anything on them, they just use spacers on the inside and change the spring length. i talked to Custom Axis last week and they said they could rebuild, re valve and lower the forks to 11 for $195. i am not sure why Jason cuts anything but he may be using forks from another source.

[sdb69z28]

Cutting them and rethreading them isnt really a big deal if you know how and have the right machine, I did a set for a roadbike a few months ago. If they arent cutting them, then they must be allowing the tube to stay farther up into the shock, losing travel. They do a really sweet job on those bikes and have put alot of though into them. Im just curious about this because id like to make a kit that you could bolt them onto a stock bike. It would be a great upgrade and alot cheaper then buying a whole bike. KTM 85 forks I wouldnt think would be big enough or have enough stopping power but I could be wrong. I would think that you would need from a full sized bike.

[fire1]

the ktm 85 forks are for the 250r not the tpc

[sdb69z28]

I understand that, but I would think that you would need a full size bike shock for a tpc, tecate, 250r or any full size trike. An 85 fork is designed for a bike thats weighs alot less than a full sized trike and a lighter rider, maybe 140 lbs guy max. I have a CRF150R and the suspension on that is awesome but im pushing the limits and that bike is well under 190lbs. Im just trying to come up with a affordable kit that makes it possible for a 250 or 450 fork on a stock trike. If it is possible im going to make a set for my 200X then try others. I can make the triples, rethread the tubes (if it has to be done), make a new hub, and axle. If it can be done and I can keep it under $1500 including forks, would it be worth it to you guys? For flattracking I would think a streetbike fork would work great, it would be similar to a supermoto setup with a taller rotor and bigger caliper.

[TommyBoy1971]

I can almost taste the tommyboy1971 build.......one more month...hehe

[jensenracing77]

Cutting them and rethreading them isnt really a big deal if you know how and have the right machine, I did a set for a roadbike a few months ago. If they arent cutting them, then they must be allowing the tube to stay farther up into the shock, losing travel. They do a really sweet job on those bikes and have put alot of though into them. Im just curious about this because id like to make a kit that you could bolt them onto a stock bike. It would be a great upgrade and alot cheaper then buying a whole bike. KTM 85 forks I wouldnt think would be big enough or have enough stopping power but I could be wrong. I would think that you would need from a full sized bike.

if you cut them wouldn't you still be loosing travel? if not i would think it would built to much air pressure on compression. you could use less oil to keep from building to much air pressure but then would there be enough oil for the damping? i guess i don't understand why you cut them over using spacers inside. mine will be 11 inches of travel when it is done, that is more than enough.

[sdb69z28]

Im just getting everyones input, I dont know what the best way is thats why im asking. If you could do it without cutting, it would be great but im just worried about the 4" of extra length. If you only lose 1" of travel, where does the rest of it go? I wouldnt want to bring the front of the bike up at all. Thanks for all the input so far guys...

[SeaBass8]

My understanding is when using the 85 forks(cr,ktm) you need to upgrade the spring to compensate for the weight. Jason Hall sells the triples with an axle, spacers, and brake hub. Or at least he was a while back. I also remember reading the Honda Goldwing triple can be used with some inverts.

[sdb69z28]

Making the triples,axle and hub is no problem and I can make them alot nicer than the stock stuff. My biggest concern with the 85 shocks is the stopping power, they are designed for alot less weight and rotating mass. Everything is heavier on a trike... If a full size fork would work then thats totally the way to go, I wouldnt want someone to be screaming down a trail at 70mph and the brakes failed. My insurance company would not be happy with me and I wouldnt feel good about it either. It has to be strong.

[jensenracing77]

Im just getting everyones input, I dont know what the best way is thats why im asking. If you could do it without cutting, it would be great but im just worried about the 4" of extra length. If you only lose 1" of travel, where does the rest of it go? I wouldnt want to bring the front of the bike up at all. Thanks for all the input so far guys...

you can space them any length you want. Axis had a set on display that only had 6 inches of travel. the other 6 inches of fork tube is inside the fork.

[Billy Golightly]

When I had the KTM85SX forks on my Tri-Z I had a larger caliper off of a 502XC (I think thats what it was) dirtbike mated on them. Another member on the forum has the KTM fork setup with the orginal 85SX front caliper (1bfc). We ride together fairly often and he doesn't have ANY issues with stopping power even though by looking at the size of the oem caliper and brake disc you would think there would be. Difference might be they are 4 piston design instead of 2 also. Some people don't like the KTM forks. But like everything, its all in setup. I've actually got a set of OEM 250R forks dialed in pretty well after a few years of dicking with them.

[fabiodriven]

Making the triples,axle and hub is no problem and I can make them alot nicer than the stock stuff. My biggest concern with the 85 shocks is the stopping power, they are designed for alot less weight and rotating mass. Everything is heavier on a trike... If a full size fork would work then thats totally the way to go, I wouldnt want someone to be screaming down a trail at 70mph and the brakes failed. My insurance company would not be happy with me and I wouldnt feel good about it either. It has to be strong.

http://i146.photobucket.com/albums/r275/fabiodriven/300R/PB080088.jpg

How's that for a tiny brake? I would guess that rotor to be about 5-6 inches in diameter. It doesn't stop as well as an 85 machine, but I know that. If I go faster than that brake can handle then that's my fault. I'm fairly certain the rotor on my R is smaller in diameter than almost any dirt bike rotor.

In other words, it works fine.

[sdb69z28]

Wow that is a tiny brake! Thanks again guys youve been a great help... What im going to do is come up with a combination that will be universal and somewhat affordable, im a firm believer in making it simple but nice. Im tracking down forks now, im not sure what fork I will use but I will keep everyone posted. I checked out jason hall stuff and it looks like a full size fork but im not 100% sure. Does he still build bikes? So for some more input... How many guys would be interested in an inverted set for there bikes if I kept the price under $1500. That would include triples, axle, hub, forks, and brakes. If its worth it I will put the time in and produce some. I have some other stuff in the works now, but im exploreing other possibilities and looking for input from you guys.

[fabiodriven]

I think being as new as you are, you're really going to have to prove yourself before people start lining up to buy anything. Lots of guys come on here and talk a big game. Results are what you're going to need.

[sdb69z28]

I understand that fully, and I understand the way guys talk, ive been in business for 12yrs and I have a brand new machine shop. I didnt spend $130,000 on equipment to dream about what id like to do. Im just trying to come up with some stuff and im feeling it out on here. Im not looking to waste my time so im looking for input. I know that once some of my work goes out here I will be busy, but im trying to figure out what parts are worth my while. Ive been designing and building motorcycle parts for a long time, im just looking for other avenues and ive always loved trikes. I built a powroll stroker 200X last summer and I came across this site, I didnt realize that there was so many guys still into them. Im not asking anyone to order anything, im asking if an inverted front end for $1500 would be worth building. Yes or No answer would be great, I will deal with building my reputation on here... my work speaks for itself. I already have parts in the works for some guys on here that have been here for awhile, so worry not...

[sdb69z28]

Back to the issue at hand... A CRF250 fork is 38" long and a 200X fork is 31" and the axle mount is about 2" up from the bottom. How long is a 250R or a tecate fork? I will figure out the best way to do this. Thanks for all the help so far...

[SeaBass8]

I think your gonna have to pickup a 250r/200x/350x and start mocking it up too see what works. On another note... Price point. 1500 is a tough one. Most of the machines we ride dont cost that much. I think you have a pretty small demagraph to sell this to. The guys converting 450 atvs are having the person doing the conversion do the fork setup at the same time. So IMO you need to gear this pruduct to someone who wants to upgrade there 250r/350x/200x. There's already someone on here that sells a "kit" to do this. It includes the triples, axle, spacers and brake hub. You'll need cr85 forks with heavier springs, brake line, caliper, disc, and bar risers. You use your existing tire/wheel and hub. The kit plus the other stuff is probably in the 1000$ range total.

I'm not trying to poo poo you, just giving my 2 cents. I would love to do this upgrade just can't afford it right now. I hope you keep working on this and figure something out that works for you.

Edit: On a 200x I think a cr85 fork would work fine. 250r/350x go bigger? Again more of my 2 cents.

[Dirtcrasher]

Jason has been adapting upside down forks with simple designs on numerous models for years now. I may be wrong but I believe had made the 1st set for Derrick Adams years ago...........

He may never have cut any, we just spoke about what would need to be done.

He was aware of a few forks that could be slid up enough yet stay off the tapered portion of the fork.

For the TPC or adapting other models a hub, collars, axle, disc, disc mount, steering stem/nut, rotor, triples, etc etc would need to be made. If a complete bolt on kit were 1500$ with forks, I can see more selling than without..........

[jensenracing77]

the basic TPC kit don't come with the forks but the entire kit is $2600. i would think if someone was going for a $1500 front end kit, they would rather go with a full TPC. i could be wrong?

[sdb69z28]

Im talking about a bolt on kit to upgrade a stock bike. If someone was going to build a tpc bike, $2600 is a drop in the bucket. I would imagine you have a lot more money to spend. You have to have two bikes to start with... A quad and a motocross bike, right? Im curious why they just dont built a complete rolling chassis, but I guess in a marketing prospective its easier to sell a $2600 kit than a $5000 roller. Anyways thats for another debate... So at this time im figureing complete upgraded, inverted front end, bolt on and be riding in the time it takes to swap over a front end for $1500. I think it can be done if its worth it, I will make one and see. More input is appreciated, you guys are the reason im considering doing this... Well plus I just like doing this kind of work.

[Dirtcrasher]

Unfortunately only a small percentage of guys here can drop that coin. Tim can make a 450 trike for about 5-7K complete. Still a 250R front (at the moment I imagine) but nonetheless, a very new and nice machine.

Look at it this way, guys won't even drop 800$+ on a rear shock, which would IMMENSELY improve there riding. That along with an invert front end may keep the 250R's and 350X's in the loop, but in this economy, who's gonna drop 3000$ in suspension alone??

Inverts are useless without the correctly tuned rear shock.........

[sdb69z28]

Good point... Well im just throwing things out there to see whats worth it and whats not, I could make some nice parts but im not going to waste my time either. Im not looking at selling big numbers im just trying to come up with a few items that guys would really be interested in. I have alot of other types of work that i do but im always looking into new things to try. I realize that im not going to get rich here but I always found that one thing leads to the next so you never know where your going to end up. The economy isnt making anyone rich right now but it is also a chance to get ahead of the curve if you can.

[sdb69z28]

Thanks for the input... I will start with some cheaper parts and see where it goes. Do any of you guys use a Vapor Trail Tach?

[Kintore]

Unfortunately only a small percentage of guys here can drop that coin. Tim can make a 450 trike for about 5-7K complete. Still a 250R front (at the moment I imagine) but nonetheless, a very new and nice machine.

Look at it this way, guys won't even drop 800$+ on a rear shock, which would IMMENSELY improve there riding. That along with an invert front end may keep the 250R's and 350X's in the loop, but in this economy, who's gonna drop 3000$ in suspension alone??

Inverts are useless without the correctly tuned rear shock.........

BTW Tim and Snake on there 2 newest builds (tim and Mine) are now using custom tripples and CR125 forks. Pic attached

Im using a stock 450 rear shock, and cr125s and I cased a tripples pretty hard on saturday, soaked it up great. Takes alot of tuning but its workable for sure. Ill let you know on 80+ tripples later on the season.
http://i3.photobucket.com/albums/y92/JoshBall/Summit012211-IMG_0260.jpg
http://i3.photobucket.com/albums/y92/JoshBall/Summit2.jpg

[Jason Hall]

The reason for shortening the forks Is because the top aluminum tube on the dirtbike fork Is just to long for a stock 250r Frame. You can't slide the forks up In the clamps far enough. The 250R steering neck Is almost 2" shorter than the Dirtbike, so you are Very limited on how far you can slide them up or down In the clamps. If you did slide them up as far as you could, the front forks would bottom out and leave about 5" under the front of the frame. The steering head of the 250R, T-3, and Tri-z Is to low In reference to the bottom of the frame to run full length forks. Shortened Dirtbike forks still have more travel than a stock R, along with better valving, It's a huge Improvement. I know for sure It can be done without shortening them, but will not work In sync with the rear. Josh, those clamps on your bike look like a carbon copy of mine??

My clamp kits are 450.00, and Include's everything but the forks and front hub. To shorten 1997-03 Cr125 forks to fit a 250r, Tri-Z Is 275.00 + seals and bushings.

[The Goat]

Or you revamp your rear suspension at the same time and run full length stuff.

I considered shortening, but I like the idea that the bike will be taller, longer, and wider... And as a result handle my big ass much better. With perfect geometry.

Soon soon soon