How do I lower my trike for flat track?

[NOS_350X]

Please Please Please Never lower it u sing the straps. That is a purely unsafe way to lower the bike, It will become rigid, bounce and twichy in the turns, Your better off running it high with suspension.

You have several options, but i would only recommend doing it with the linkage, or buying a shock setup to lower it.

[ForeverThreeWhe]

I think me and the old man are going to make a lowering link tomorrow. I'd buy one but they are $163 locally and I don't have time to ship one over here to Australia.

We'll be using 2 of these...

Spherical Bearing Tie Rod End 12mm

http://bit.ly/15tEs3p

With a threaded rod in the middle. What do you think?

[barnett468]

Can someone please measure the distance from centre of eye to eye of one that's fully lowered. Would it be stock length + 2 inches?

You must shorten it. Your rocker has a progressive ratio of approximately 2:1. Shorten link 2” will lower bike by approx 4”.

xxxxx

The heim idea is a reasonable one when the link is made strong enough to be safe.

The heim you posted a link to looks either low grade domestic or Chinese and I would not use that one. Use a high grade Aussie, US or Japanese made one. The proper and safest way to make an ADJUSTABLE link is the following.


1. a. Buy good heims

b. buy HARDENED all thread, either grade 8 or B7 4140 steel. Do not use std mild steel all thread, this is a high load area and it can easily bend.

c. 4 thin nuts preferably hardened

d. buy 2 us feet of thick wall 4130 chromolloy tubing with an id small enough to be drilled and tapped for your 12 mm all thread maybe between 11 mm or less.

2. Put bike on stand, remove old link, pull rear end up with tie down to desired ride height then measure eye to eye where link goes.

3. measure the distance from the eye of the heim to the bottom of it and multiply by 2, measure the thickness of 1 nut and multiply by 4, add these 2 totals together then subtract it from the new measured eye to eye length of the link then take that number and subtract 5 mm for a little more adjustability and to compensate for any errors in measuring and MACHINE cut the tubing to that length on a lathe. It can NOT be hand cut. The ends must be perfectly square or the nuts will instantly come loose.

4. chamfer top inside edge slightly then tap 90 mm deep.

5. measure your orig link eye to eye and subtract your “new” calculated length from that. Divide this number in1/2.

6. take the number from above and add 20 mm for depth of heim and 40 mm for minimum penetration into tubing at full extension which will be the same length as stock link then cut all thread with whatever you have, lathe, cut off wheel, band saw etc to this length.

7. install heim in vice with shop rag to prevent damaging heim and tighten gently

8. thread all thread into heaim 20 mm then install nut and tighten well on heim then remove heim and repeat process on the other heim.

9. install nuts on all thread, thread until it bottoms out on the other nuts.

10 thread into tubing until it bottoms out, then install on bike and adjust to desired ride height and tighten nuts firmly onto tubing.


PLAN B WHICH I’M GUESSINNG YOU ARE GOINT TO DO.

1. Use hardened rod in place of tubing, measure and cut to appropriate length using the applicable numbers above.

WARNING – T his will be an unsafe link. It should be used for low load conditions like smooth tracks with no jumps. The all thread will bend if used under high load conditions.

BOTOMING OUT – Your bike will easily bottom out using a shorter link without putting the appropriate length travel limiter [spacer] on the shock shaft.

SPRING – You will need to pre load your spring slightly for short track, this will raise your rear a bit [around 30 mm] so account for that in your link length calculations if you want.


LOWERING FORKS – Do as previously suggested by another member by switching springs around, fine tune height by raising or lowering tubes in clamps. If you do not have separate top springs then you can cut your long one by the same amount you want to lower rear by, flatten the ends with a torch and pit the new short spring in bottom side of fork tube.

TIRES – As another member mentioned, if you use lower profile tires than stock you will not need to lower the bike by the link as much, account for what you are going to do in your link calculations.


Have fun at the race!

[ForeverThreeWhe]

You sir are a genius. Thank you.

[barnett468]

Hello

Thanks, it's not really that hard, I've just done this stuff since the dark ages, lol. Feel free to ask any other questions you might have about it. I'm sure if I can't help you someone else will. If you really want to try and make the link the first way I described then just do 1 line at a time, you won't get overwhelmed with info that way. If you can read a tape measure and you can read [which I'm sure you can] you can make the link, lol!

[Bryan Raffa]

SINCE ITS SO QUICK,, back off the preload,then take a tiedown strap and go around the back of the frame and the back of the swingarm carrier area,, get a big guy to set on it and pull it down till the footpegs drag the ground!!! them go have some fun!!!!!

we had a guy do this once at a indoor ice race .... as we line up .. one of the guys notice that it was wrapped up in the sprocket... as thousand watched two guys on ICE try to pull this strap out ... LOL it didnt look good ... and held up the whole show.. couldn't imagine what would have happened in the first corner!

[ForeverThreeWhe]

I managed to lower it approx 2 inches today by undoing the preload.

Before


After


I also widened the right side 2.5 inches. I'm thinking about widening it another inch by using a Durablue block type spacer. What do you guys think?

[ForeverThreeWhe]

The Track:



It's Big! Approx 450mtrs and 16 mtrs wide. It's very wide as they race cars on it too

[barnett468]

Hello



That;s a very nice bike!

That is a nice track. Pro 3 wheelers may hit around 120 kph plus on that.

They may require a front number plate with large numbers. Don’t stick them on until you get there in case you can’t run the number you want.

Have you ever raced before?

Do you plan on going WOT or just cruising around in a circle and having fun.

I’m guessing you haven’t raced before.

I suggest you get there early to get acclimated to everything.

I’m guessing your swing arm is stock length and your steering stops are uncut this means that if you get it sideways it can spin out on you VERY quickly. The lower they are the less likely they will tip over when this happens.

There may a few guys in your class that should be in the next higher class and they may “bump” anyone in their way that’s going slower than them.

If your front tire gets more than 30 cm off the inside of the track you will likely get bumped and/or passed. My opinion is the middle of the track is the safest for new riders. You can watch everyone else crash from there too.

I would run your rear tires around 12 lbs not much lower. It will have less traction this way but this means it will slide easier and therefore will be much less likely to “dig in” in a turn and high side you because your bike is so high.


Hop at least some of this info helps.

[barnett468]

Hello


I managed to lower it approx 2 inches today by undoing the preload.

This will only work for low “race” speed non aggressive beginner or novice level racing. It’s a long story.

Look at Bryan Raffas bike, that has a ride height for 80 mph pro oval racing.

xxxxx

I also widened the right side 2.5 inches. I'm thinking about widening it another inch by using a Durablue block type spacer. What do you guys think?

Are you saying you want to bolt a spacer to another spacer? I personally would never do that for several reasons.

[barnett468]

OK, #45 saw it in the second photo cool.

[ForeverThreeWhe]

Thanx mate for all your help. I appreciate it.
I used to race flat track / short circuit as a junior on a 1990 CR 80 many yrs ago.
It's only a practice day. In fact it's the first trike "racing" event in over 25yrs in Australia.

All the details can be found here.

http://www.ozatv.com/forum/viewtopic...b0d678aaeb93bb

[ForeverThreeWhe]

Yeah I was considering bolting the 2.5 stud spacers on the right to another 1 inch block spacer. Probably not the safest idea ever.

[barnett468]

Hello


Thanx mate for all your help. I appreciate it.

I used to race flat track / short circuit as a junior on a 1990 CR 80 many yrs ago.

Very cool, I was doing mx and a couple TT races, [smooth track with some big sweeping turns and 1 jump]. Lot’s of fun! I was a pro motocrosser then and our work had a fun day where we all went to the TT night races, huge track 80 mph down the straight. I was on a Yamaha 400 and our shop mechanic who was a pro short track, tt and mile gut blew by me locked up totally sideways feet on the pegs on a little 200cc triumph cub pro tt bike, lol. Embarrassing.

xxxxx

It's only a practice day. In fact it's the first trike "racing" event in over 25yrs in Australia.

25 years that’s horrible, just rent the track and hold your own races.

xxxxx

All the details can be found here.

Cool

[poohbee1]

a 1/4 mile+ sprint car track is not a good place to experiment be carefull and good luck