| Author | Message | ||
     Ratbuell |
So, in an attempt to keep my cardio in shape I purchased a 2017 GT Karakoram Comp MTB last year. I'd ridden a GT all through college and would still be riding the same bike today, except that when I had my big accident in July '08 it was hanging on hooks outside my garage (being the middle of MTB season). By the time I was mobile and on my feet again - around Christmas - the frame had managed to take on water, which froze, and split the frame. Fast forward to now, and I'm loving the new one. It's a 29r with hydraulic discs front and rear; hardtail, with a Suntour XCM HLO 100mm front fork. And, the fork is the only issue I have with the bike. I run it, honestly, locked-out most times. It's a spring fork, with hydraulic lockout. The spring is too damned soft, and under any sort of aggressive pedaling...it pogos. I've tried running a partial lockout...no joy there either. I guess the 3 way adjustablility on my Buells has me spoiled! My question - if we have any MTB'ers here - is what my options may be. I'm on a tight budget at the moment due to extremely slow income. Is this something I can put a stiffer spring in? Convert to air? Or am I looking at a new air fork (or even, at this point, a solid carbon fork and just bag the suspension altogether)? It seems that the ideal end product is going to be either a solid fork, or an air fork so I can set my own tension as opposed to being locked into a particular spring rate. Any thoughts or advice? | ||
| Aesquire |
http://forums.mtbr.com/shocks-suspension/confused- about-low-end-suntour-suspension-forks-640272.html Midrange hydraulic lock out. I'll check with my bike shop buds. Different springs are available & it uses a replaceable cartridge for damping. Check the Suntour site for tuning. Also rtfm. There might be a knob to twiddle. Partial lockout? My old Specialized Stump Jumper is the long obsolete full suspension steel frame and the Manitou Ti fork was middling hot for it's day. | ||
| Ratbuell |
The lockout is a rotary and yes, I can turn it a partial turn for partial lockout. The spring rate is still set for a 5 year old. I'm no whale but I do go 180, and with extremely long legs I have some serious leverage on the pedals when I'm digging uphill. I use it mainly for cardio, and will freely admit I went MTB for durability. My technical days and rockhopping days are long gone; the extent of my main cardio route is some unimproved roads and a short trail section. I did look at the exploded diagram, pretty straightforward construction. I'll check with the shop where I bought it and see if they have any ideas for me. Seasons slowing down, I get home after dark now, so a little downtime won't hurt too much. Although I much prefer the cycle and the scenery, to the rowing machine in the basement! | ||
| Court |
Bring the bike when you come . . . . I'm in the midst of eliminating 70# and have a route you'll love. | ||
| Fireboltwillie |
should be able to install a stiffer spring. look up the make and model of the fork online and see what spring/repair kits are available. | ||
| Sifo |
Suntour XCM HLO 100mm front fork. Looks like a fork aimed at a low price point. It would be worth looking at a stronger spring, if you are OK with the fork otherwise. There may not be one available though. Are you bottoming the fork on a regular basis? Slight bottoming a few times per ride is fine, but if you are slamming it down regularly, you need a stronger spring. If you are not bottoming it frequently, but just don't like the travel when hammering, you might be better off with a fork that has a shorter travel option. Many with adjustable travel, do so by compressing the springs as they limit travel. You basically wind up with a boat load of pre-load on the spring as the fork is stopped from extending upward. It's not what I look for, but might suit your riding desires. Looking at their website, it looks like the specs say 100mm, 80mm. Is there an external travel adjustment? If so I would try that at the 80mm setting. You might be able to add a pre-load spacer. Not ideal, but might work out for you as a budget fix. Heavier fork oil might help a bit, but is a huge bandaid for your issues. BTW, a zip tie on the fork tube is the best way to gauge your fork travel to really see what's happening, both on various bumps, and to see what kind of bob you get when pedaling. Just zip it down enough to stay in place though. No need to zip it down tight. | ||
| Aesquire |
100mm is the spacing on the front wheel hub. Understand, I have hard core biking buddies, and while the market changes with time, I may have to ask what level "Alevio" is, for example, I run equipment that is solid, but not usually super premium. I do this because I'm a 200+ pounder who sometime rides over my skill level, and can turn a Kmart bike into scrap in one day. I also learned that low level gear hurts. Literally. You have a chinese chain snap when hammering up some single track, your testicles may be demolished. A wheel that tacos on a 2 foot hop can slam you face first into the broken glass on the street. So my road hardware isn't running Campangnolo.... Or Dura Ace. But I do run Shimano 600 & 105. ( I'm looking at my 600 brakes with 105 levers as I type ) My mountain bike gear is Deore, but not XT. ( and my Buell has Showa, not billet ) The point is I run good enough, tough enough, but almost never the very best, since it's generally not better, just prettier. So, today, I'd run the $600 fork on a new bike, not the $1200 one. Maybe even the $400 fork with $100 better springs. I'm still checking to see what your cheapest upgrade path is, my bike shop buddy is checking for me. I do suggest taking the bike to a small, independent shop, where they've got the enthusiast mechanic types that ride as a lifestyle. They'll know how to set up the fork and brakes ( critical ) and how to get the best out of what you've got. Setup is critical. Consumer reports a few years back tested some mountain bikes and rated a Brand x bike as awesome, and a Brand Z bike as junk. The thing is, other than the decals, it was the same exact bike, same frame, same factory, same parts. Exactly. The difference is the human at the shop who assembled it from the box. One local shop I hang out at has a lunatic running the place and every bike he assembles gets the hubs etc cleaned, and lubed with premium stuff. ( he'll even put Campangnolo ball bearings in the local racer's bikes ) Then he gives everyone a lifetime warranty, and urges them to bring the bikes back, often, for lubing and adjustment. His bikes, ( the low end ones from the same factory as the Kmart model ) last a long time and his customers are loyal. Some day he'll be gone, but bikes from Freewheelers will still be out there. | ||
| Bandm |
I was looking at bikes and saw this in the comments. My favorite thing is the ability to add stuff onto the bike, the weight, and the handle bars. I'm suprised more bikes don't use these for comfort and to take pressure off the wrists. I've never owned a bike with suspension before and this feature excites me for when I'm riding on trails and unpaved roads. I have town it around the neighborhood and to a friend's house over 5 miles away... the ride is smooth. The seat is good, it doesn't pinch me anywhere unkind like others out there and plenty of cushion. The only thing I do wish it had were more options for mounting fixed accessories. For my daily use, I'd like a spot on the left or right side of the frame near the fork (out of the way of my legs) so I can mount a holster for my carry weapon so it doesn't print through my shirt while I'm riding. http://www.7milecycles.com/product/trek-ds-4-27657 2-1.htm | ||
| Thumper74 |
I love the broad interests of Badweb. I worked in a bikeshop in high school and mountain bike heavily. I have a GT Traffic now. For your needs, I don't see why you couldn't add a preload spacer to the spring and/or go a step up in oil weight to slow the compression, too. | ||
| Ratbuell |
I think I need to focus on the spring. High speed stuff feels fine - rocks, branches, pavement chunks - and that tells me the damping Is good. It's the low-speed spring action that's way too spongy. Pedaling hard (or even moderately hard) and it's a pogo stick. I'll try and dig into some more research and see if there are different spring rates available, or if a spacer is a possibility. This is an entry-level fork, I know that; not sure how many options are out there for it or if it's a case of "replace to upgrade". I know it's easy to spend the price of the bike or more, just on a serious fork...and I don't do any technical stuff to make that a worthwhile spend these days so I have a feeling if I have to replace...I'll just get a solid carbon front end and be done with it. | ||
| 99buellx1 |
Last year I bought a used Specialized Epic Comp. It's way more bike than I need, but it was a good deal. I've not rode near as much as planned this year, life has been in the way. I'm not going to claim to be up on this stuff, but I think even an entry level air fork would be ideal. You can easily adjust it for your weight/needs with a simple pump. Or, if it needs different feel you can drop in a cheap spacer to vary the characteristics. Pretty sure you could find something that would work for your needs in the sub $200 area. | ||
| Ourdee |
The suspension and drive train geometry at the rear could be the real problem. Think of how jumping on and off of the throttle 90 times a minute effects your Buell. | ||
| Ratbuell |
The frame geometry is pretty much the same as the GT I owned for 20 years. I'd have to check specs to get exact measurements, but side by side and light ride-around (the frame is freeze-split, but still functions for driveway work) it feels identical. If the old bike was disc brake, I'd pull its Rock Shox front end and swap it. Well...if it was disc, and a 29r. The old was a 26" wheel. I may go air. Again, though, it comes down to money (rather, the lack thereof). Right now, admittedly, I'm doing about 85% pavement and the 15% non-pavement is pretty much just gravel; no trails or anything like that. I get home from work and end up riding in the dark, which puts me on the decommissioned military base a half mile from home. There's a 5k run marked out on the property - no traffic, no real danger other than if I get tackled by a deer, and I've got a good app that I've used to map out my nightly 5 mile ride. After a full day at work, 5 miles is enough. Sub-20 minutes, right around 400 calories, and great for the cardio. And that's my primary use for the bike - again, I went MTB for durability because I know me...and I know I won't always stay on pavement. No sense getting a cheap road bike and taco-ing a wheel or snapping a frame because I decided to see "what's down that trail?". | ||
| Sifo |
It may be largely a user issue. If you haven't done a bunch of cycling, you may be kind of ham-fisted with the pedal stroke. Pedal bob is normally a problem when hammering up a hill out of the saddle. That is what the fork lockout is for. If you are in the saddle, spinning away, you should be smooth enough to not have any serious bob issues. It's extremely common for newer riders to simply hammer away on the down stroke, instead of actually pedaling a circle. Sure, you foot will follow the pedal on a circular path, but you just aren't as smooth as you should be. So is this an issue when spinning in the saddle, or only when standing/hammering? If it's only when out of the saddle, either get used to adjusting the lockout, or get used to the bob. Even with a proper spring, you will bob when hammering. Have you checked your sag? The zip tie I suggested earlier will tell you a lot. Slide it to the top of the slider and gently sit on the bike in your riding position to settle the fork. Be careful not to bounce it down. You can lean an arm or shoulder against a door frame or something, or ask for a helper. A typical XC fork should use about 25-30% of travel on sag. Even more of an issue, is how often/hard you bottom out. Again, the zip tie will provide a lot of information when checked after riding over various terrains. Bob is just a compromise you get when you add suspension to a bicycle. How much you find acceptable, is kind of a personal thing. Most forks do feel pretty soft when set up correctly. Even my 8 inch down hill fork can be bottomed by just slamming my weight down on my arms. It still absorbs huge hits when riding though. The pedal bob is just silly when climbing a hill though. The suspension and drive train geometry at the rear could be the real problem. Think of how jumping on and off of the throttle 90 times a minute effects your Buell. It's a hard tail, so not an issue with the rear. | ||
| Ratbuell |
I'm not a newbie...out of practice maybe, but not totally new  Valid point though. I rode for a little bit with the stock pedals; recently I've switched my old pedals onto the bike, with toe clips. When seated, I'm not only pushing down but I'm also pulling up and pushing forward. My leg issues from my accident in '08 make me VERY conscious of even strokes/strides. I'm on the bike because I cannot run, and I cannot use a treadmill without severe step-impact pain. Wintertime, I replace the MTB time with elliptical time in the basement. Boring...but good cardio. Most of my issue is when standing and pedaling hard. I admit it's a tradeoff for having suspension, I just wish I had some more preload or some air. Does anyone make a progressive-rate spring for MTB? Or is that only in the $1500 fork sets? I don't bottom out; sag and overall stroke are "acceptable" according to the zip tie (I do the same thing on my Buells). There is a "preload" dial on the left fork, but it's never done a damn thing. At least not anything noticeable. I guess, given my usage and preferences...either I need to look for an inexpensive air setup, or just bag it and go solid for now until I can afford a higher-end suspension fork (or until I have bumpsteer issues on downhills). | ||
| Sifo |
I've got a bike with a Cane Creek air shock on the rear. It's light and adjustable. Those are the pluses. It uses air for the damping circuit, which doesn't work well. Oil damping is much better, but adds weight. Worth the trade off IMO. I've wound up rebuilding it about every 1,000 miles or so. I find it to be a PITA once it doesn't hold pressure even for a few days. It requires the pressure to be checked on every ride once it starts to wear. Those are down sides I've experienced. I know air has gone through a lot of development, and has become quite accepted, but I'm still gun shy of air. | ||
| Aesquire |
The word from my bike shop buds is buy a new fork. Rock Shock or Manitou mid range, $350 price range. I don't think your technique is bad, and maybe a spacer can help. Bottom line is the Suntour is better than the worst ( some damping) but is built simple and cheap. I once had a Lawill girder type fork that was a handling dream, solid fork tracking and natural anti dive. A bit heavy. A buddy bought my bike to get the fork for his. Currently running an ancient Manitou ti fork that's still running fine with a decade of single track. | ||
| Ratbuell |
I'll just keep an eye out for a higher-grade fork. I figured the OEM was a 'budget' unit; I'll just run it locked-out for the time being. I did get a new back tire. Managed to grind all the lugs off the original, so went with a more street-friendly pattern with a kevlar core (for strength on those occasional gravel/trail sections), since the majority of my cardio ride is pavement. I like buying bicycle tires a LOT more than I like buying motorcycle tires! Bike shop guy: "yea, this one here is kevlar, it's a tougher core, a lot stronger...but it's a good bit more money... ...it's $50, instead of $30...." |
