Hi 640Adv Guys, Need a little help here. Long story short I have been trying to do the right thing and give my local KTM shop the business but it ain't going well. Started about 9 months ago, I ordered new fork and shock spring last April, it took till late july to get the fork thing right. As a matter of fact I was the guy in Ouray on the BMW R100GS PD because the springs still where not in and I had the bike apart because the promised they would be here by thursday and I was leaving Montana friday morning for Colorado. At the last minute I left for Ouray Friday morning on the GS, they did not get here till mid august. That is enough about that part. Finally got the rear spring in last sept and it was not even close[was 210 in length, should be 260]. So they returned that one and the correct one???? came in today. What I had order in the beginning was an 8 spring rate in 260 length from checking on advrider as what would work for me. I go about 220lb with out gear or luggage and ride a little hard but not jumping over cliffs. The one that I picked up today was a WP factory spring but the numbers are 8.1/9.9-260, QUESTION OF THE DAY will that work. I gave up talking to my local dealer because they don't have a clue, that is why I'm looking for some info. My guess is that this 8.1/9.9-260 might be one size heavier than the 8.0-260 that I ordered. If so it still might work for me just a little stiffer than what I had in mind. By the way the heaiver frok springs make a world of difference in the front. Any body got an answer??? Thanks flyshop
All it means is that you got a progressive rate spring... 8.1~9.9 kg. in a 260mm length vs. the stock 7.0 or 7.5/260mm straight rate spring. Considering I run a 9.2 straight rate on my Adventure, which falls almost in the middle of your progressive, it should work out OK. C
Thanks creeper I'll give it a shot, it has to be better than the "lite" stock one. thanks again flyshop
I'm probably the wrong guy to ask that Meat... I've never quite understood the concept of a prgressive spring in most applications. I believe the idea is to have a relatively soft inital rate to soak up the little shit, then as the suspension becomes more compressed, which it would in a big hit, the firmer high spring rate kinda takes over as the softer rate coils would become (close to) coil bound. I suppose there are plenty of theories to support progressive and single rate states of mind. C
It should work fine, and because the lower rate is still heavier than stock, that should eliminate most if not all of that wonderful "mushy" feeling us 200 plus pounders have come to know and love.
I just put a new spring on my Adv 2 days ago. Go to http://www.precisionconceptsracing.com/Precision_content.html Give them a call, tell them what you need and they will send it to you no problem. They are $109.00 + about $8 bucks for 2 spacers.
That's deep baby... (said by Shaft) I pondered, and my 2hp generated a thought, but then I read your last post to flyshop and that makes good sense: even if he is progressive, it's all above his current spring rate so he should be at least better than that.
Here's another way to ponder it. As no part of the rate is less than 8.1 then the effective minimum rate is 8.1... which would make 9.9 the effective maximum rate. My bike, plus gas, plus me, plus panniers, plus shit in the panniers adds up to around 680 lbs of stuff, and I imagine flyshops all-up weight is very similar...so his average effective rate of 9.0 is right in the hunt. My "fun with math" method of consideration is probably an idiotic way of looking at it... but then consider who you're dealing with.
680 all-up wt. = 9.0 ave. effective rate ... couldja connect those dots for me please. your idiotic way is above me - don't like the way that sounds but there it is! that aside, I am hip to the groove you're layin' down daddy-o. i just thought i remembered something about the progressives behaving differently than linears and that not necessarily being a good thing off road (in some opinions). i brought it up because i remembered something about them and thought that, even though flyshop is DONE waiting (damn that was a long wait for some springs... and made ya miss taking the 640a to Ouray... ), he might wanna know about this behavior difference so he can be ready for it and acclimate to his new spring type. maybe i will have to contact one of these suspension shops and enquire.
Well, some quick FAQs reading and: http://www.racetech.com/SubMenu.asp?cMenu=4&c=Yes&cSubMenu=11&showPage=#5 so i guess that recommendation was for the forks and not necessarily for the shock. memory can be a problem sometimes. some good info nevertheless. hm, does flyshop's bike have the PDS shock? i thought it was only the earlier ones... but just in case: More about the PDS shock here: http://www.racetech.com/articles/ktm.htm the 2003 640a has a linkage so perhaps it doesn't need a progressive spring and the above info on behavior might be helpful? even for flyshop? stock spring rate for the 2003 is 7.0 kg/mm :huh so by what you were saying creeper, that is pretty darn low for us big boys and our stuff... unfortunately their shock spring calculator is on the fritz so i can't check what they would recommend quickly. For the front their calculator (200lb rider wt.) recommeded .48 kg/mm springs; stock was lower I recall. so both ends are soft as beat to death over and over again here and elsewhere.
hm, does flyshop's bike have the PDS shock? i thought it was only the earlier ones... but just in case: My 640 ADV is a 2001 and the 48 front springs is what I put in the forks and they are great, made a huge difference. Thanks for the info flyshop
Back to progressives first. My little example of "fun with math" is really just a bullshit way of trying to categorize the un-categorizable. It's hard to determine just exactly how any progressive spring will perform on a particular bike unless it is tested. Why? Using a theoretical "10/50" progressive as an example, lets say its 10 lbs to compress the first inch... groovy? Now, when does the 50 part go into effect? In the second inch, the third... maybe the fifth? Without testing... you don't know do you. Now, lets put that spring on a rising rate, linked rear suspension. What is the leverage ratio and is it a linear ratio... or has a progressive curve been built into it? Do we want to create a "compound progressive" with a progressive spring on a progressive rising rate? Unless you own something like a Race Tech Shockclock, all you can do is trust the advice of the people that do own them and have (hopefully) tested your combination. Suspension ain't as simple as some would have you believe. Forward to why a 9.2 or anything else for that matter. As to the use of a particular weight of spring, again I defer to the actual suspension experts and ignore the interwebnet experts. How many times have you seen someone say "Oh yeah! The 8.0/260 is the way to go!!!" Yet no one considers that the person doing the talking is a relative beginner... or an expert, or weighs 175 lbs, or weighs 245 lbs, or put the spring on a LC4E, or rides in open desert at 80 mph, or carries 70lbs. of shit in panniers that have more of an effect on the bike than a 70lb. heavier rider because of the positioning of the weight, or rides in deep dark woods at 5 mph, or... get my drift meat? I can go on like this for days, because that's how many variables there are. I went to the man in Tacoma, I told the man this is what I weigh, this is what my bike weighs and this is how I ride. The man and I talked for a good half hour. The man in Tacoma called the man in California and told him what was what, and that man punched the numbers into the Magic Spring Gonkalator. The man in California called the man in Tacoma and said 9.2 in the back and 5.2 in the front should be El Supremo combination so sayeth the MSG Does this mean that Flyshop's or that Craigincali's spring sucks and I'm the only one with the right spring? Nope... it just means that the right spring for me is a 9.2. That was fun, C
no, really, how did that math work? 680 all-up wt. = 9.0 ave. effective rate on the rest of that, i follow and agree. suspension is a black box to the reasonable folks who are not experts, and probably best left to experts or folks who have tried the setup as you said. I would just add that Race Tech said that in the front the oil is alread progressive so progressive springs tend to make the front too progressive in their experience so they usually recommend linear up front. In the rear, the linkage is progressive as you stated, so they usually recommend linear, but again it depends upon how progressive it makes the bike and if that jives with you, your setup, and your style, and the phase of the moon tommorow... so that is why i agree: take it to the guys who know. thanks for the jabber creeper; nighty night
