| Author | Message | ||
     Jpfive |
Dang, I hate to jump in here...  I appreciate you referring to the spring dampener as 'damped', bjunky, as that is where my comment and question reside. How is the spring damped? Seems to me the weakness of the spring dampener is exactly that - you may well have undamped harmonics from the spring itself, especially in aggressive riding. Jack | ||
| Trojan |
So the only variables I see in the "Damped" Pulley that could be a detriment to performance would be how long the spring can deliver optimum tension, and how resistant to twisting the system is, as twisting could cause belt alignment problems. The spring only allows around 6-8mm of movement once installed. This isn't enough to cause any 'harmonic' issues but is enough to damp the worst of the shock that is applied to the belt under heavy acceleration or over bumps etc. We have used them in racing under 'very aggressive' riding conditions, and they have covered thousands of miles on the road with no issues whatsoever. Replacement springs are available from us, and we recommend that they are checked during service intervals and changed after 10-15,000 miles. The unit is manufactured from billet aluminium and the design ensures that it cannot twist (unless something breaks or is installed wrong, which is extremely unlikely). The bottom line is this really: I don't say they work because I sell them. I sell them because they work | ||
| M1combat |
I don't get it... Maybe I'm dumb. You let off the throttle and you add tension to the bottom side of the belt. This tension compresses the spring and allows for a longer belt path. You then get back on the throttle and all that slack in the top side (that you wouldn't have had with the stock setup) is removed forcibly. The belt doesn't "stretch" .010. The belt path length changes .010" from fully extended to fully compressed. As far as I can tell it's tightest when the suspension is extended. You can easily rotate the idler pulley in either extreme, and it takes about the same amount of torque to do so. How many customers do you have that have over 50K miles on their bike with the spring loaded tensioner that you can pretty well say for sure wouldn't have made it this long without a bearing failure if they had the stock setup? I only ask because I have 50K miles on mine and nary a single bearing failure (aside from that one early on because I dropped it into first twice without using the clutch). I just don't see it. No matter how you slice it the spring loaded tensioner can ONLY reduce tension and increase the slack. Goodyear wanted MORE tension for increased belt life. That said... I'd rather run a stick through mine with a spring as opposed to without a spring . I can see how it could help in that situation. I can not see how it could help suspension movement, and I think that the slack generated on the top side during deceleration has the potential of helping to attain the shock loads needed to snap a belt. | ||
| Redscuell |
This is BS; what's the answer to the original post ("Has anyone found a spring loaded belt tensioner for the 25r"), if anyone actually knows? | ||
| Trojan |
The answer so far is: No there isn't one, yet. There you go | ||
| Xb9 |
If I remember correctly the OEM pulley has more of a function than just keeping the belt tensioned. I believe when the early XB's were released that the factory claimed there is some benefit in anti-squat and keeping the geometry and traction optimal under excel / decel conditions. I wonder how the spring loaded aftermarket pulley affects that? | ||
| Jpfive |
Ah, c'mon Red, we need to have this discussion at least quarterly... Trojan, you're a good guy, and I love the way you take care of business. If I was ever to become convinced of the efficacy of the dampener, I would buy it from you... I agree with your last comment, M1... Ride safe, all Jack | ||
| Dirty_john |
Well then, at the chance of prolonging this debate I thought I had made it clear that if the gearbox pulley and swinging arm pivot are concentric then the belt tension does not change and a spring loaded tensioner is not needed to satisfy this issue. But the spring loaded tensioner also allows for debris getting momentarily caught between rear pulley and belt and by the spring compressing reducing the risk of belt breakage and/or pulley damage, why do you think Buell fit such large belt guards? Even with these there is a risk of debris like a stone chip getting in there. As soon as my 1125R is delivered I will be looking at the overall layout, it may be possible to modify Trojan's XB tensioner to fit, which I intend to do. | ||
| Jaimec |
It's NOT a "Dampener!!!" It's a DAMPER!!! Sheesh! | ||
| Trojan |
As soon as my 1125R is delivered I will be looking at the overall layout, it may be possible to modify Trojan's XB tensioner to fit, which I intend to do. Hi John. I don't think it will be possible to adapt the XB tensioner to fit the 1125, for a couple of reasons. Biggest and foremost reason is that the stock 1125R tensioner wheel is mounted directly to the footrest assembly, and does not have a mounting 'arm' as the XB does. This would mean that the 'sprung' part of the assembly just wouldn't fit I'm afraid. The only way that I can see to incorporate a sprung tensioner onto the 1125 would be to include the moving piece as part of a complete new right side footrest assembly. Alternatively a separate bracket would have to be designed that would hold the tensioner wheel in the stock or close to the stock position and still allow some movement. This would be complicated and difficult to achieve without looking a bit 'Heath Robinson' I think. One other reason that the 1125 may not need a sprung or damped tensioner as badly as the XB models is that it is fitted with a 'compensating' front sprocket I believe, unlike the XB. This acts pretty much like a cush drive would on a 'normal' chain drive machine and will absorb a lot of the 'shock' that is the killer of XB belts. Given all of the above, I doubt if the movable tensioner would be applicable to the 1125, although I have yet to have a close look at one just to make sure, so never say never | ||
| Jaimec |
I was told the XBs already had a cush drive in the front pulley as well? It was stated as the reason it would be easier to convert to a chain drive than the old tuber models (which relied on the belt itself to act as the "cush drive"). | ||
| Redbuelljunkie |
I find this information absolutely fascinating... please continue. | ||
| Chadhargis |
This is one of those posts I'd like to see someone from the factory chime in on. Any engineers out there wanna envoke their Anonymous rights? | ||
| Trojan |
I was told the XBs already had a cush drive in the front pulley as well? It was stated as the reason it would be easier to convert to a chain drive than the old tuber models (which relied on the belt itself to act as the "cush drive"). Definitely no cush drive in the XB I'm afraid. The front sprocket is a solid mount to the gearbox output shaft. The XB is not really any different to the tubers in terms of converting to chain drive and in fact is slightly more dificult because of the lack of axle adjusters. However, we and plenty of others have run chains on their XB's for years with no ill effects, and have always used a 'race' 520 guage chain rather than the established 530 guage used on most Tuber chain conversions...although of course chain conversions are another can of worms entirely and can be guaranteed to open a whole new thread  | ||
| Jaimec |
Matt, I just noticed that at low rpms I didn't have to slip the clutch as much with my XB12Ss as I did with my M2 Cyclone. At very low speeds if I didn't slip the clutch the Cyclone felt like a jackhammer with the power pulses from the engine going directly to the ground through the undamped rear wheel. I never noticed this effect on the XB12Ss which I could run comfortably in first gear at just above idle (I do that a LOT in our traffic). I haven't noticed this issue in my new 1125R either. | ||
| Zac4mac |
Dirty-john, you hit the only reason I can see to run one of these - debris, especially sand. I leave the guards on and stay out of sand, belt is very happy. Zack | ||
| Trac95ker |
A friend of mine measured the distance (the path of the belt)around both pulleys using a string. He did this with a rider's weight on the bike and with the swing arm fully extended. He found a 3/4" difference in length. IMO I don't think Goodyear designed the belt with that kind of tension in mind. The spring loaded belt tensioner does not allow dirt to do anything. Dirt gets in between the belt and the pulley because the tires pick it up off the ground and centrifugal force overcomes the sticky tires and the weight of the debris and it flies in to the pulley, belt interface area. The spring loaded tensioner deflects if the tension load on the belt increases for various reasons( dirt, suspension tops out). Hard acceleration (shock load) could be another reason. | ||
| Slypiranna |
IMO, Minor dirt/sand is allowed in compression of the belt's composition to a certain designed/degree...far better than a spring. The design of the fixed idler system (1125R/CR) is comprised of more engineering than many here are capable of fully understanding. The belt's engineering is over the top when you really understand what it does! The 1125R/CR cannot be compared to prior examples. I admit, I'm one of the first to look for improvements or question why but I cannot see any reason to attempt bettering this one trait of the 1125 models. (Message edited by slypiranna on November 10, 2008) | ||
| Trojan |
The spring loaded tensioner deflects if the tension load on the belt increases for various reasons( dirt, suspension tops out). Hard acceleration (shock load) could be another reason. You have hit the nail firmly on the head there The tensioner isn't really designed to solve foreign object issues but it does so as a side issue, although only with larger stones etc. Sand wouldn't make any difference whichever tensioner you use. | ||
| Slypiranna |
Bottom line to all this? I find it VERY hard to effectively "argue" with the original design engineers that spent years and at least a few hundred + (?...perhaps more?) thousand dollars in developing the 1125 model's fixed belt/idler system with fixed pulley and all the geometry/math, r&d and over the road testing. Think about the other effort being involved, as a supply to this "food chain"/Goodyear?! What do you think that they afforded? To think all chain drives still have all the slack that they do, supports this post. This is almost 2009. The technology being applied for public use has proven better than a what a "spring" can overcome. Put a fork in it, I say... This subject is proven all good by BMC...perhaps, years ago... just like the other fundamental patents that are about to expire of Buell origin. Seems like like many manufactures are going with under belly pipes? | ||
| Trac95ker |
The belt tensioner is in the same boat as the XBR headlights. They have to cut corners somewhere to make the product affordable like someone mentioned above. The belts breaking don't happen as much or cause as much of a problem as the headlights. They did redesign the whole pulley belt system for 04 and came out with newer stronger belts in 06. They changed the geometry to further improve the design on the 1125R. So for you to say this subject is all proven years ago doesn't make sense. if it was proven, no more belts would break. Kevlar or what ever fiber they use does not like to be stretched and I think that is part of the problem. It wouldn't surprise me if they came out with another belt design. They design is great but not perfect. I like my belt with a spring loaded tensioner. It works well. If it worked so well, they would of used it on the XBRR with an adjustable tensioner but they went with a chain. | ||
| Slypiranna |
There is no such thing as "perfect"...otherwise, everyone would be out of business? I don't need an answer to that one... My main angle on posting to this thread is that which I've stated... How can anyone, with a formal engineering education, argue against what is exampled within the 1125R/CR's final drive as being questionable? Perhaps the better question is this; Whom, among "us"...and all are invited...have the means to prove this subject wrong? Please...post your mechanical engineering degree's ('ssss) with your next shot as I will bet on Buell's engineering unless you can better them! You never know, BMC just might hire YOU with your post alone!  At which point, I'll kiss your golden a$$!  Now...where do I place these fish lips?  | ||
| Paint_shaker |
Buell says fixed tensioner... Belt manufacturer says fixed tensioner... Belt has lifetime warranty with fixed tensioner... I am sensing a fixed pattern here... That being said, in theory a sprung tensioner should allow for front and/or rear pulley changes... Any company up to researching a sprung tensioner that would allow for pulley changes while using the same belt?? | ||
| Slypiranna |
Now...that'll work Paint shaker! Good idea! Who's steppin' up? | ||
| Trac95ker |
There is no such thing as "perfect"...otherwise, everyone would be out of business? Then you said: How can anyone, with a formal engineering education, argue against what is exampled within the 1125R/CR's final drive as being questionable? You are contradicting yourself. A quick search in the 1125 section came up with 21 results for broken belts. There is your proof  you don't have to be an engineer to realize that when you twist the throttle and don't move that there is a problem! Whom, among "us"...and all are invited...have the means to prove this subject wrong? Please...post your mechanical engineering degree's ('ssss) with your next shot as I will bet on Buell's engineering unless you can better them! I don't have to,Free Spirits already proved it  Looks like you better put some lip gloss on and pucker up for Free Spirits.  | ||
| Slypiranna |
And you own an 11 or have relevant info regarding these "21" failures? Nothing personal, just the facts. Free Spirits is behind your post surrounding the 11? | ||
| Trac95ker |
There are people on this board who own 1125r's that have had belts snap. Thats a fact. If you choose to believe it didn't happen, you have the right to. I am in no way affiliated with Free Spirits. I think they have a good idea, thats all. I believe the Buell engineers strive to create the best product they can. I also believe that the accountants force them too make compromises. | ||
| Rfischer |
I just LUV how this goes 'round and 'round, driven by those who have something to sell. As Sly sez, post up yer curriculum vitae, gents....along with the engineering documentation for whatever doo-hickey you're pushing. | ||
| Trojan |
I just LUV how this goes 'round and 'round, driven by those who have something to sell. And the Buell Motor company is entirely altruistic of course, has no thoughts of profit but just wants to spread the word of Erik by giving motorcycles away? I think you will find that when it comes to making profit, the manufacturers (and I include Buell in this) make a lot more than the small aftermarket manufacturers and retailers do. Also, if you think that just because an engineer works for the factory they must be right, you are being niaive methinks Plenty of factories have thought up bizarre and unworkable engineering solutions over the years, sometimes solutions to problems that don't really exits anyway. You think Buell are exempt from this? Think back a few years to fiasco of Tube frame shocks that could easily have driven the company to the wall, and which it is still trying to recover its reputation from. Never mind the rest of the recalls over the years, or 'updates' to replace parts that were either badly designed or badly manufactured. Lastly, do you really think that a factory engineer is any more qualified than someone like Marcello at Free Spirits or Julius Ilmberger, or Thomas Voll at RRC, or other qualilty aftermarket manufacturers? These people's reputation and livlihood hange on the quality of their products, and if a product didn't work it wouldn't be sold for very long? They cannot hide behind a large corporation if things go wrong, so your arrogant assumption that 'company men' are in some way better qualified makes no sense whatsoever. Whilst I am sure that they are well qualified it shouldn't be taken as read that they are in any way better than someone who runs or works for a small business. | ||
| Jpfive |
Trojan is a sponsor of this board. He has every right to defend and promote his products here. 'Profit' is not a dirty word either. Although it cannot be accurately stated that a business person has a 'right' to a profit (would that it were so), it is certainly a requirement. Jack |
