It's at 50mm rake right now. I'm still trying to figure out if I like it better or worse than 60mm...60mm was pretty cool.
Frame design
- Thread starter Ted Wojcik
- Start date
Ted, I would like to hear your take on extending and gusseting the seat tube like the Scout. Perhaps its just an aesthetic issue for me but the ever-extending seat post bugs me somehow.
What are the pros and cons, from the mind of the frame builder, of making that seat tube, say 21" and giving it a gusset for support?
What are the pros and cons, from the mind of the frame builder, of making that seat tube, say 21" and giving it a gusset for support?
The issue I have with an extended seat tube with a gusset is that when the gusset is welded on, there is significant distortion of the top part of the tube. This makes reaming the tube a bit of a PIA. I like to use an externally butted seat tube and the butted section is not long enough to allow much of an extension. I think it is best to have a good amount of the seatpost go below the top tube seat tube intersection and prefer not to have any more steel in the frame than needed
I find it particularly hard to continue forward progress when my wheel is at 3 and 9
I like that bottom bracket figure -should still keep it within 12" or so even if someone were to run Stans and low PSI in their tires.
Will this design feature sliding dropouts or standard vertical rear dropouts?
I will put up some photos over the weekend. Sub 17" stays with sliders XT front der, 2.3 tire, and LX crank. I'm trying to make a 29er mainstream.
What I'm trying to do here is make a 29" wheeled mainstream mountain bike that shines in New England single track. The priority is the ability to turn and burn, point and shoot. Long bikes don't make the grade. The challenge is big wheels. The bike needs a long front center, that is the distance from the bottom bracket to the front axle, to prevent toe overlap and short chainstays to weight the rear wheel to help with lofting the front wheel. We know that a 29" rear wheel has more traction, but the bigger front wheel is heavier, so lofting will be harder. Light weight is important. It is the mass of the bike that needs to change direction, so the lighter the better. Short bikes mean less steel. When it is all done, we will see what the road tester has to say. I have put the chainstay/B.B. assembly together today and I'm happy with the way things are going. Stay tuned
Rode the 16.75 stays today for the first time. I'm not going to comment fully on it until I've had a week or so in the saddle, but they do make an immediate difference in pulling the front up. The high (12.75) BB also allows you to carry much more speed through rock gardens...There may be a couple drawbacks as well, but I need to get used to the whole new setup before coming to any conclusions...
I'm not an east coast resident but I have to ask; have you put in any time on a sub-17" chain-stay bike on tight, twisty trails? Even here in the soggy northwest, I can feel the advantages (or at least the difference) of short stays on my Simon Bar vs. my previous two frames built up with the same components.
I think the bottom line here is that a central theme or motive for this project is creating a potential production frame based on short stays. There are already a fair number of long stay frames available so there's no point in going there.
As an aside, I don't see the attraction of long-travel 50lb downhill bikes. However, I'm not going to pipe up about it in the downhill forums.
i spent the my entire racing career as a junior on a short chain stay 16.75" stayed bike actually. it handled great, but there were a lot of other things that influenced how it ride and well my riding style has changed a bit.
and honestly, there are way more short stay bikes on the market right now. it's kinda the new fruit booting.
and honestly, there are way more short stay bikes on the market right now. it's kinda the new fruit booting.
Reread post #168. Some people drink light beer, too.
On that we can agree. Alas, those poor mis-guided souls...
Tonight's libation here, NOT a light beer...
Smuttynose IPA
Holy macaroni and Cheese...another Mickey
Pretty soon you'll tell me my 29er sucks and begrudgingly admit the 650b is the way
this ted Guy is A-OK in my book. I know Chris L, so I had faith, but this seals it.
big difference, i'm still racing! oh man.Holy macaroni and Cheese...another Mickey
i won't tell you that your 29er sucks. ok yes i will, and probably pick on you the entire time i ride with you.
hahahahahahaha
I was actually just IMing Mickey and he was saying just the same stuff I typed...He's a riot...I hope the Spooky thing works out.
Oh man. Sounds like some freaky movie where everyone is all normal and stuff in the day, but one night a comet flys by and **** gets weird...I mean really weird. One guy, Barry (Mickey can play Barry if you want) is all chill till he sees the comet and he just loses it...eats a ton of Meth and gets jinked out of his freakin skull...you meanwhile, the charachter named Ned, are practicing bocce in the back yard (yeah I know it's weird, night bocce, but you just wait, it will catch on...). So anyhow, Ned is looking for his Pallina, wandering around in the dark, when Barry (remember this is actually Mickey) comes tweaking around the corner...he's chewed his socks off and his now working on an old Bell helmet...he can't really see you, but he can smell you (hey, there's a comet, weird stuff happens...) he skids to a stop and starts juggling the balls (bocce balls you perv) and ned (you) darts at Barry because this is CLEARLY against INBA Bylaws (International Night Bocce Assoc). You (ned) move to tackle Ned, but he gets the drop on you and he flips you around and starts to eat your socks...
You freakin LIVE with Mickey? Steal that set of Middleburns and send them to me
Okay, here's the deal. Using slider dropouts, we have .8 inches of adjustment. With the sliders all the way forward, there is a chainstay length of 16.85 inches with about .35 inches of clearance between the tire and seat tube. With an e-type front dérailleur, we can set the stay length at about 17.25.View attachment 93396
View attachment 93397
View attachment 93398
View attachment 93397
View attachment 93398
What a nice way to spend a Sunday morning. Good coffee and photos of a 29er design in progress. 
Could you also go back a little bit more than 17.25" if you wanted? Or is that all the way back with the sliders?
Also, if at some point a rider wanted to try an "old school" or older era Front Derailleur on the frame - what clamp size would be required and would the cable route from the top tube down or from the downtube up? My Surly used downtube cable routing, My Inbred and the Redline I owned would have utilized TT cable routing had I used gears. Just wondering.
Best,
Mark
I tried some older XT dérailleurs and there is even less room in front of the tire.View attachment 93399
View attachment 93400
View attachment 93401
View attachment 93400
View attachment 93401
I love how that steel looks right now "in the raw" and all.
I should snap a pic of the old LX that is on my son's hardtail. It came from and old Schwinn Hardtail I picked up for $20.00 at a local bike shop. It is very streamlined for lack of a better word. I think it is a 31.8 mm clamp size.
I should snap a pic of the old LX that is on my son's hardtail. It came from and old Schwinn Hardtail I picked up for $20.00 at a local bike shop. It is very streamlined for lack of a better word. I think it is a 31.8 mm clamp size.
With a bit of manipulation of the stays, there is decent tire clearance between the stays with the 2.3 Exiwolf. There is enough clearance at the tail of the dérailleur cage and tire. So it seems that to run a new Shimano dérailleur , 17.3 is about as short as the stays are going to get. Bending the seat tube wont help because the height of the tail of cage above the chainstay would be affected with a more vertical seat tube at the shell as viewed from the side. There are differences in front dérailleurs from Shimano based on chainstay/seat tube angle. Bending the seat tube would make the angle outside of those specifications. I'm going to go ahead and weld up the frame this week and when I get it together, I'm going to try a road front dérailleur and see if that helps. I want to put it together to see if mtn shifters will index a road dérailleurView attachment 93402
View attachment 93403
View attachment 93404.
View attachment 93403
View attachment 93404.
Ted - I sent you an email and also you've got a private message.
A road front derailleur might work - although road triples never seem to shift as good as doubles. But maybe that is something specific to road bikes vs. mtbs.
A road front derailleur might work - although road triples never seem to shift as good as doubles. But maybe that is something specific to road bikes vs. mtbs.
Yup, I love the three B's. Bikes, Beans (coffee), and Beer. Contrary to popular belief, bottom pull cables work better that top drive. As the rear derailleur cable runs down the seat stay the rear tire throws crud all over it and it runs down inside the housing and causes drag and sticking. Bottom pull will also give us more room in front of the tire by getting the cable out of the way. There is plenty of adjustment of the sliders to give as much clearance as we want. I'm happy with everything but the front derailleur clearance. I would like to use a 28.6 seat tube so that a 27.2 seat post could be used without issue.
I just found some spec's on SRAM X9 front derailleurs that show more room for the tire. Will Shimano shifters work with it? Do we want to consider SRAM drive train?
Nothing wrong with SRAM whatsoever in my book. Whatever works best and makes the most sense for the build is what I'd vote for.