After building two frames at ETB over the last two summers (one in the course, one in a more guided fashion using their workshop), I’m preparing to build my first fully solo frame - which will be a XC/Gravel-y 29er Hardtail for my wife. She rides very mellow off-road terrain and could probably use a gravel bike, but was also jealous how playful my bike felt when she rode it with the dropper all the way down, so sticking similar to what many are doing with their geometries. 74.5 STA, 67 HTA, 58 BB drop and 430 CS Length and ideally sliding dropouts (looking at Tange LR30, does anyone know if the paragon slider inserts fit on these? ), with a 120mm fork.
However, having a bit of a tricky time figuring out what tubes I would best go for. Considering she’s not a very strong nor ambitious rider, I think I can err on the sider of lighter instead of stronger. I was considering a 38.1 .7/.4/.7 downtube , 31.8 toptube (but not sure what thickness, a .9/.75/.55/.9? ), ext butted 30.9 ID seat tube for a bit of weight saving (I’m aware I’ll have to squish the toptube a bit to fit here) and a T47 to allow me to offset that seat tube a bit.
However, I’m clueless for the stays. Order a Zona 29’er bend, build a dimpler and hope for the best? Zona triple bend? Will I need a yoke for sure? Trying to model chainstays in BikeCAD isn’t the easiest, and I feel the CS Length is making it tricky regardless.
Personally I would go with smaller diameter, thicker wall on the front end. But I’m interested to hear others takes.
Check out Deda MPO240C2022 chainstays. I can clear a proper mtb tyre and a 55mm chainline 34t chainring on a 73mm BB comfortably without dimpling anything. You may be able to do the same by moving everything inboard a little for your XC/ gravel frame. You can also offset them to the bottom of that T47 BB shell to gain more chainring clearance.
The last time I made a long-low-slack 29er, out of Columbus and Reynolds, only Columbus had the tubes in the thinner gauges (and the appropriate diameters and lengths). Idk if they still do. But you may have other suppliers if you’re in US. I think for any normal rider who isn’t sending huge jumps and things thinner gauge is better. That’s part of the point of a custom build.
Wish I could be more help on the stays My experience has just been to buy them, draw everything up on the table, and see if the tyres you want to use will fit. If not then think about yokes or what you’re going to do. Worst case you end up buying some different stays and having some left over for the next build.
I feel that going much smaller for the downtube would look a bit out of proportion for the 46 headtube? I personally prefer a 38 (or even bigger, but decided that doesn’t make sense here) for looks, but if it’s not advised I’ll stay away.
I’ll model those stays up - they have been in my temporary shopping cart before but actually forgot all about them and had only been looking at Columbus stays the last few days. Thanks!
And yeah, this is a 65kg rider who would rather walk than send - so not too worried about strength in general
This one is more on the gravel/ CX side of things and for a pretty tall order (obvs). I believe the Kona Honzo uses 35mm tubes throughout the front end too, might also help to have a look at those. Not trying to sway anything, aesthetic is v personal. Just offering references
If this is your third frame I’d shy away from the super thin-walled tubes. Not sure if you’re brazing or welding the frame together, but I either way it’ll be less stressful to work with thicker tubes. You can save weight with lighter components or ditching the sliding dropouts.
For a hardtail, I’d go with:
HT: It’s hard to beat the Paragon Machine Works EC44
TT: 28.6 9/6/9
DT: 34.9 9/6/9
ST: 34.9 1.6/9 for 31.6 post (Andrew at bikefabsupply.com can bend the tube for you). The 30.9 externally butted tubes look too thin at the top IMO.
BB: BSA
CS: Not sure since I bend my own for a yoke. Somewhere on this forum there’s some ideas for making your own yoke out of laser cut plate steel.
SS: It’s best to bend your own 4130 tubes IMO. There are inexpensive ways to do this with handheld tube benders.
Thanks for the advice, I’ll take a look what 9/6/9 tubes I can easily get as I’m based in mainland Europe and would prefer to keep my ordering within the EU.
On the HT: I was looking to just buy a plain tube from Deda or Columbus, but I could spring for the Paragon one. Any benefits besides having the headset areas reinforced already?
On the dropouts: that’s actually an area where I had a lot of doubts. The sliding assembly ends up being quite expensive, and some people do claim they slip and creak. However, it saves me from having to deal with the brake mounts and allows for adjusting CSL… What other dropouts would people recommend for a beginner builder? Many of the hooded types look quite small to me, so I’m worried about having enough area to braze on.
As you’ve already figured out, sliding dropouts make life easier when it comes to the brake mounts. Just get the insert you need, and you’re good to go.
I’ve built a number of frames with sliding dropouts. Both Paragon (incl. the rocker style) and Allotec, and I’ve never had an issue with creaking. Slipping is not an issue since you have a tensioner bolt to hold the inserts in position.
Plenty of space on the hoods if using stays that taper a bit. But if you’re planning to use non-tapering stays, you may be better off looking at plate-style dropouts and slotting the stays instead.
For my first 29er build many years ago I splurged on a Columbus tapered HT. It comes with braze-in cups that act as reinforcements. If just using a plain tube, definitely look into fitting reinforcement rings.
An alternative to PMW for Euro builders may be Bear Frame Supplies. Shipping may be a bit more affordable from the UK even though they’re outside of the EU.
I wish conventional PMW sliding dropouts would have eyelets (even on the insert…)
Also, if it can do a mini hijack: would the folks here recommend 16mm seatstay (0.7-0.8 thick) for a max rear load of 40lbs (+ 20lb front load and frame back for 200lb total weight) or should it be beefed up? Thanks!
Here’s an option I used for a customer who wanted to be able to use a rack. It required that the rack mount holes be drilled larger and to buy longer slider bolts but those bolts are bombproof and it all looks integrated both with and without a rack. I used a seat collar with mounts for the upper arms.
The issue is any rack mounted solution where the eyelet is machined in the droput will usually puts the rack legs in the way of the caliper/housing. Mounting off the insert will be even worse. It’s pretty tight back there with sliders.
Best options I’ve seen is to just put regular old hourglass mounts off the seat stays (as is the way on the latest Kona Units), or you can check this reddit post where internally threaded bolts were used. Pretty neat and by the looks of things the legs sit just wide enough to clear the caliper. I remember someone also having some custom extra thick double washers laser cut that had an eyelet added to them. Can’t find a picture of that setup though. Good luck!
