Fork Springs

[steveloomis]

What about the rear spring for the 84 to 89 xt's? Any suggestions. I am going to order one of each of the front springs kits from Progressive. I am heavier than my son so this will be a good test of two almost identical bikes.

I really appreciate this info...

Steve

[xtzrick]

What about the rear spring for the 84 to 89 xt's? Any suggestions.

Click on the link in THIS thread & there's a word document giving the spring rates Ohlins recommend for different weight riders on different bikes

Rick

[manco]

I raided this pick from another forum.

I figured it would be useful for tuning in various XT600 fork springs.

Click on the pic to bring up a larger view.

[tall-mike]

Hey Steve,

at 240 lbs. this is what I upgraded to: Hyperpro rear spring part no. sp-ya06 ssb 010 at $139. <info@epmperf.com> NJ phone 732 786 9777 Regards Mike

[steveloomis]

Do you feel it was a worthwhile investment? I assume firmer and more controllable ride. I don't like the nose dive as I am sure my springs are weakened with age and I weight a bit (quite a bit) more than 30 years ago....

[tall-mike]

A little extra weight...that's nothing, having part-timers I can't remember how soft the suspension used to be seriously the rear spring is much stiffer and an automotive alignment shop only charged 20 bucks to swap the springs out. ( a motorcycle shop wouldn't do the work) Mike

[steveloomis]

I have inquired to Hyperpro about the SSB010 spring and the SSB009 spring. I inquired on eBay and they sent me a link to their web site. Again no listing for the 86 XT600, just the 88 and greater XT600z Tenere. I am assuming the suspension is very similar. I have some progressive front springs en-route, found them on eBay for 80 bucks and change and free shipping. These are the 1141 models, Am I correct that these are softer than the 1506 model spring. Since I will need two sets and one rider is heavier (that's me) and one is lighter(my son) this should work out. Perhaps the softer is good enough for both of us.

Any comments? I'll pass on what I find out and how the work for our weights.

Steve

[manco]

It seems odd that they would ask you to increase the viscosity of the oil. I always understood, with increased spring rate you would want less compression dampening and more rebound dampening. Obviously with fixed orifice forks you cannot alter the ratios between compression and rebound dampening (without a drill ). By increasing oil weight, you increase compression dampening.

Of course the real proof is in the ride! How does it feel to ride Bosley? Have you gone over any unexpected potholes?

My 1990 - onwards XT600E Progressive Suspension Spring Part # 11-1506 arrived a few weeks ago. I finally got around to installing them in my 1986 XT600 43F. The springs are long & stiff. The initial rate runs for about 65% of the length while the final rate occupies about the last 35%. They fit in the fork tubes without spacers. This is how Progresssive recommended they be installed in 1990 - onwards XT600e as well. Progressive also suggests no air in the forks with their springs & 10w. I opted for 5w Maxim fork oil when installing the springs though as I wanted a faster moving fork to start tuning with. I chose the Maxim brand as it was the heaviest 5w option that was reasonably affordable. I plan on raising the fork oil viscosity in 2.5w increments over the next several months to get a feel for different oil weights in the fork.

I have only ridden the bike around town so far. The bike feels different with the stiffer springs and 5w fluid. The ride is firmer from the springs & quicker with the 5w oil. Overall my initial impression is that the fork setup now feels not so sluggish, more responsive then the stock springs. The bike has much less brake dive now that is for sure. When I grab the front brake the nose starts to dive for an instant then the springs hold firm at a good height. I haven't hit any rough stuff on the springs yet. In a few weeks I will be in the desert. I will be bringing some ten weight Maxim Fork oil & an air pump for further tuning while out in the desert. While I am there I am sure I will find a pot hole or two to hit for testing purposes.

I am happy with the springs thus far. I will still be keeping my stock springs for different tuning setups though. The stockers are nice for putting around on. I like to deflate them forks & rip around with a short quick front end in town & on two lanes. The stock springs will be better then the stiff progressives on snow & ice too so in the winter they will still be handy to have. I would like to get the softer set that Progressive makes for extra tuning options. That spring set would fall between the stock and the Progressive XT600e springs. Eventually I would like to add a set of cartridge emulators to the forks. All those parts plus 5w through 20w fork oil viscosities would make for an affordable XT600 fork tune kit with three spring rates, dampening adjustability & approx. 7 weights of oil dampening options. Intermixing the Progressive springs with other brands of springs would be the next step in such a kit so as to have more spring rates to tune with.

[manco]

Have you gone over any unexpected potholes?

More riding today & I started to get the hang of the new springs. They require a more hard on riding approach then the OEM springs. When the handle bars are driven like you mean it the springs keep the bike holding well. Corners are a lot more exciting. The spring have a lot of dig in. Bump handling is superb. I charged over a median today making my way to a pretrol station. The fork handled it great. It charged an 8" curb and over several more inches of dirt & pullled then descended doing a 90 degree turn. The springs sucked up the curb, tracked the dirt & rebouned with enough force to hold the wheel firmly to the terra firma through the it all.

So far my thoughts are these springs would make for good sport springs for an aggressive rider, a good firm spring for a 180lb to 220lb rider & a good medium spring for riders over 220 lbs. Riders that ride timidly probably will find this spring a little unnerving. These springs in a 43F's fork need to either be weighted down with a load or driven hard to get them to really do there thing. Lighter weight riders even if aggressive may find these springs stiff too. Probably the lighter spring rate that is recommended by Progressive & other companies for the 43F would be a better all around spring for day today riding for such riders. Riders that want something stiffer then these springs should opt for one of the other spring rate choices that are greater then these. Riders that tour with a load would probably find these springs to be adequately stiff for basic touring I would guess too.

Of course what do I know though. I have only tried this spring set & a few sets of 30 year old OEM rubbish. For all anyone knows I may just be blowin the smok I be




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[manco]

...In a few weeks I will be in the desert...

Just got back from the desert. I came back with two words to describe the springs, "Bad @ss!" These springs are the best mod I have done to my XT600 & the first one I would recommend to anyone. I never messed with the fork oil. I ran 5w the whole time cause it ROCKZ!!! The only adjustment I made was this; I ratchet strapped the forks as compressed as I could get them, then I released the air pressure in the tubes, then I released the ratchet straps & uncompressed the fork. This created a vacuum in the forks & helped create a little more preload against the springs.

The springs absolutely ripped in the desert. I road everything from open desert to insane technical rock. Never once did I feel the fork was holding back the bike like it does with OEM springs. 5w is the way to go for off road I feel. 10w or +, maybe for the road & hot weather??? I am sticking with 5w until I find reason to switch. 5w provides the speed I like in a fork off road.

Some final thoughts on XT600E Progressive Suspension Spring Part # 11-1506 installed in a 43f fork on a 43f XT600:

Rippers need look no further for a good all around spring.

Lighter riders or lazy Sunday drivers will probably prefer a softer spring.

Big time rippers that want to pull 40' tabletops with their XT600 may want something stiffer, or maybe theses springs + psi in the forks would suffice???