View Full Version : Will this suspension set up work?

10th March 2005, 06:42
I want to get my sporty to sit more upright and level, less dip in the back. I know I could change the back wheel to a bigger size (16" to 18") and that would do the fix rather quickly. However, I wondered if an idea I have would work and not affect handling too much.

I was planning on changing the back shocks anyway getting a set a bit longer than stock. So with some longer back shocks and then move the front fork tubes about 1/2" to 3/4" up in the triple tree would it meet my desire without hurting the front end handling? I would then get a bigger back tire to even out the look of the wheels.

This is all part of my plan to get the street tracker look without spending a frickin fortune in parts. I like the look of flat track racing bikes and how they sit upright with the big tires and minimal accessory look. Anyway, your inputs and suggestions are most welcome. Thanks in advance and much Aloha from Hawaii. regards, chieftd

10th March 2005, 13:12
Don't mess with the triple trees! ...

I am no suspension expert ... but if you want your bike to set up higher in the rear, your really want to get longer shocks. You didn't say what year or model your bike is, so I don't know what length your stock rear shocks are now.

You should just remove one of the rear shocks and then measure the length (mount bolt hole to mount bolt hole). Get a new set of Progressive shocks at least an inch or maybe an inch an a half longer.

Also, installing new Progressive front fork springs will make the bike handle much better too, but normally raises the front end just slightly ... so that's something to consider too when replacing the rear shocks.

Good luck,

10th March 2005, 13:40
:D Chieftd,

I run my custom with the forks between 1-1.5" up in the triple clamps. I would recommend getting progressive fork springs though. She will bottom out on a big bump without them, especially if you ride two up.

Changing wheel diameter doesn't always get you much for the bucks spent. You may spend a lot of money and only get .5" or less in ride height. The difference in the 21" front wheel/tire on the Custom is negliable over the 19" used on the Roadster due to tire height differences. The 19", does get you a wider front tire foot print.

Flat trackers and street trackers usually run 19" wheels front and rear. That pretty much limits you to Dunlops. The tire is more dirt than asphalt friendly. They also have 18" tires. :rolleyes:


10th March 2005, 16:33
Its a 1989 Sportster XLH with the stock 16" rear and 19" front 9-spoke cast wheels. I'm just looking for ways to cut corners cost wise in the conversion. A set of new 18" 40-spoke wheels is about $1200 without the tires! I actually like the look of the 9 spoke wheels and would like to keep them. I have been searching for an older 18" cast wheel for the rear but haven't found a good one yet. I definitely want longer shocks in the back and will look into changing the springs in the front as well. thanks, chieftd

10th March 2005, 16:41
Like I said ... Longer rear shocks if you want to raise the rear ...

10th March 2005, 17:27
I lowered the front of my bike by sliding the forks up in the triple trees an inch. Changing over to progressive springs would be the best way though. Also like Turbota has said, change the rear shocks out for a longer set. Changing wheels and tires will not help as much as you might think. It would be like going from a set of 16" wheels with 245 55r16 tires to a set of 17" wheels that run 255 50r17 tires on a car. The wheel will be taller but the lower profile tire will make it the same height as it was before.

11th March 2005, 13:45
Moving the forks up in the trees is absolutly not a problem. We have moved the forks up and down on nearly every bike we build. It does nothing to limit travel either.

11th March 2005, 19:44
Thanks to everyone for their inputs. I'll definitley get the longer shocks for the back and go from there. Aloha from paradise. :) Regards, chieftd

Nu Viking
12th March 2005, 05:38
If your 89 has the same tripple trees as my 86 you well not be able to raise the fork tubes higher into the tripel tree. the upper fork tubes are taperd at the top. I say a lowering kit is in order and if you feel the bike became to low, try some dampening plugs to get the right height.Taller shocks on the back well give you a real cushy ride but I had one small problem. I was loaded,,,,,, let me refrase that, the bike was loaded with camping gear and beer for a campout at my favorite spring rally. when I stopped and threw down the kickstand. I went over to shake hands with a buddy and my bike and gear fell over on the kickstand side without the kickstand closeing or digging into the ground. 20 years ago that would be embarassing but what can ya do besides laugh and start setting up camp.

12th March 2005, 08:10
Put some longer shocks in at the rear and slide the forktubes through the trees at the front. There is no need to remove a shock to measure the lenght of it!
I had some clearance problems with the muffler bracket after I put on the longer shocks. But my Sporty has a secondary chain and not a belt. :shhhh

12th March 2005, 14:24
There is no need to remove a shock to measure the lenght of it!

She's right ... but if you don't just remove a shock to measure the length, you need to put a lift under the bike to get the weight off the rear shocks so the lenght can be measured while the shocks are fully extended.

Either way, you need to find out how long your stock shocks are before you can figure out what length you want for the new shocks.