Frame Size Opnions Wanted - SS Bikepacking Rig

[bmike-vt]

Newb here when it comes to the specifics of MTB sizing. I'm building up a XC / bikepacking SS / FG ( for future gears) 29r based on a Soma Juice frame. Use will be for dirt / gravel / single track.

When I built up my brevet / rando rig I did a thorough fit / sizing and had a custom Ti Indy Fab built.
Money is not in the wallet for that endeavor - and I'm salvaging parts from my FG CrossCheck to move to the Juice - so initially it will sport V brakes and a rigid fork until I wear through the rims and build some disc brake wheels.


On sizing it seems local consensus is that I should get the 16" or the 18". (about evenly split amongst my 'experts').
By online calculators / guides I seem to fall into a ~17" frame.
Comparing the numbers I can see how either the 16" or 18" might work...

So - for a Tour Divide (buildig a strategy to do it the year I turn 40) / Bikepacking rig - would the larger bike better serve this use - with shorter stem and seatpost?
Or should I push out the stem and seatpost on the shorter rig - esp as this will be a 29r.?

My last MTB was a 'large' Yeti FRO and it always felt too big, regardless of how I setup the stem / saddle. Its moved to a new home so I cannot easily check measurements.

I've been riding dirt / mild single track on my 54cm FG/SS Surly CrossCheck with a 12cm stem and Mary bars. Comfy enough but the geometry doesn't suit aggressive terrain (virtually no standover height!).



Experience / Opinions / Ridicule wanted and welcome.
I've looked at the Karate Monkey and the Redline Monocog Flight.
The Soma comes recommended from a local adventure racer.

5'8" tall
Cycling inseam of 84.5cm
I'm on a 55cm custom Club Racer with a 11cm stem and Nitto Noodles (24 hour events, centuries, and brevets)
I also ride a 54cm Surly CrossCheck (road and dirt) FG with 12cm stem and Mary bars.

[bmike-vt]

Large size ordered based on the advice of a local adventure racer and 24 hour mtb racer.

Can't wait to build it up.

BP trip in the cold happening tomorrow... on the road or cross rig, depending if I want gears or fixed.

[Pivvay]

I order based on effective top tube length assuming the seat tube isn't crazy short. That's really all that matters to me, well maybe also HT/ST angle. The rest I just work around and it's insignificant (to me). I tend to like to be stretched out more on long rides and like 90mm to 105mm stem lengths. This puts me on a larger size than sometimes people would guess.

If your custom bike was right on, I say get the one with the ETT closest to that.

[rocky rode]

If your custom bike was right on, I say get the one with the ETT closest to that.

I mostly agree, Chris.  The first thing I look at on a frame is ETT length, then standover and head/seat angle.  But, if his custom frame was designed for drop bars he would have a shorter toptube than a frame designed for flat bars.  My road and cross bikes have a 55 cm TT and my 29er has a 23" (58.4) TT.

Gary

[Pivvay]

Very true. I was only thinking flat bar MTB to flat bar MTB. I've never run drops or other alternative bars so i forget about those! good catch Gary.

[bmike-vt]

Thanks for the input.
Similar thoughts to what my local shop has said.

The small looked good by the numbers - but when he took all of my current specs from both bikes (saddle height, reach, frame geo), he pushed me to the 18". On the 16" I would have had as much seatpost showing as there was seat tube. The longer ETT should combine with a decent HT size and angles.

Another concern he had was working with the bike / vs. being perched atop it - and since this will be a semi loaded XC platform, and I'm not one to do super technical terrain (it will be rigid) - he felt being a bit more stretched out similar to my road rig would be a good fit.

Gary - I'm on 55's too - but the ETT on the 16" would have been only 2 cm longer - the 18" is 23.6" (actually 600mm as listed on the spec sheet) so I'm picking up some real estate to the cockpit - but HT size and angle and not needing the stack height and 14cm stem I need on the cross check should favor the longer ETT. Should hopefully get me back to a 90 or 100cm stem. I could even live with 80 if the handling was not compromised.

Should be here by Friday so I can get to the woods before the snow flies... but snow is good too... looking at upgrading my BC XC skis to a lite tele setup... then I need some painful time on the hill to remember how to turn. Been awhile since I've been on the MTB or skis in the woods - having a little one certainly changed the 'play time' equation.

[rocky rode]

Gary - I'm on 55's too - but the ETT on the 16" would have been only 2 cm longer - the 18" is 23.6" (actually 600mm as listed on the spec sheet) so I'm picking up some real estate to the cockpit - but HT size and angle and not needing the stack height and 14cm stem I need on the cross check should favor the longer ETT. Should hopefully get me back to a 90 or 100cm stem. I could even live with 80 if the handling was not compromised.

Mike, for what it's worth I run an 11 cm stem on my road bike and a 10 cm on my cross bike, both with 55cm TT.  On my 29er I have used a 10cm stem but like a 9cm (with barends for climbing) better for techy stuff.  So, I'd suggest starting with a 9cm and maybe give an 8cm a try to see which you like best.  I also run a flat bar with 11° of sweep which effectively shortens the reach a bit.  It sounds like you're on the right track.

Gary

[Slowerthensnot]

Standover has been an issue with some frames and my shortish legs... esp with a loaded bike can be an issue esp noticed it using my fisticuff frame vs jabberwonky frame on the colorado trail this year.... 

[bmike-vt]

yeah... hoping my local 'expert' considered all of the #s i sent over, including looking at the standover.

now to figure out gearing.
currently on the the crosscheck i run a 17/19 dinglecog rear and 38/40 up front.
the low end @ 19/38 is too tall for the woods when it gets steep and rooty.


i have a 17/21 dingle on the way. so maybe i'll see a 32/38 or 30/36 up front.
and there is the 22t freewheel i have mounted flip side that i need to calc into the equation.

or maybe i'll just figure out something reasonable for fixed to the dirt, then ss in the dirt.

[rocky rode]

now to figure out gearing.
currently on the the crosscheck i run a 17/19 dinglecog rear and 38/40 up front.
the low end @ 19/38 is too tall for the woods when it gets steep and rooty.


i have a 17/21 dingle on the way. so maybe i'll see a 32/38 or 30/36 up front.
and there is the 22t freewheel i have mounted flip side that i need to calc into the equation.

or maybe i'll just figure out something reasonable for fixed to the dirt, then ss in the dirt.

Mike, I've been running dinglespeed since 06.  I like to coast though...  I run 32/21 and 36/17. Live at 8,000' in CO and go up from here.   I love dinglespeed, I find getting to and from trails too boring with just a trail gear and I use the higher gear for a lot of jeep roads, two tracks, etc.

Gary

[bmike-vt]

Gary - are you flipping a wheel or using a dingle ss freewheel setup? I'm having similar thoughts - would love to mirror my FG setup which I think is going to work at 32/21 and 36 or 38/17. White Ind. only offers their DOS in 17/19. Any other options out there?

[Slowerthensnot]

Gary - are you flipping a wheel or using a dingle ss freewheel setup? I'm having similar thoughts - would love to mirror my FG setup which I think is going to work at 32/21 and 36 or 38/17. White Ind. only offers their DOS in 17/19. Any other options out there?

ss cassette hub you can stack a few surly cogs no prob... dt, wtb, and i think there's a few cheaper options as well

[rocky rode]

Gary - are you flipping a wheel or using a dingle ss freewheel setup? I'm having similar thoughts - would love to mirror my FG setup which I think is going to work at 32/21 and 36 or 38/17. White Ind. only offers their DOS in 17/19. Any other options out there?

I'm using a Hope Pro 2 SS cassette hub with two cogs on it.  My bike (VooDoo Dambala) has sliding (vertical) dropouts and I can do the gear change in just a few seconds, I use a QR skewer on the axle.  By having the same total gear teeth 32/21 and 36/17 my chain tension needs no adjustment when changing gears.

Using a hub with a thread on freewheel limits your options to White Ind. I think.

Gary

[bmike-vt]

thanks to both of you.
good info.
i'll keep that in mind, as i'll eventually be building up a disc brake wheel for this ride...

[bmike-vt]

Well - got the fit dialed in. Longer stem needed than I thought - I'm running 11cm now but have a 12 in the mail. Gearing is daunting. I'm running fixed now. 34x21 is way spinny. It might be great as a SS but as a FG getting around on the flat is maddening. It might be perfect for the steep and technical - but the woods are coated in wet leaves and muck right now so I've been keeping it close to home.

SS is beginning to sound better and better for offroad - although I will miss rear wheel control. I'll run fixed all winter though and play with SS options come spring.

Building a disc hub front wheel too... Coming together nicely.   

[bmike-vt]

Getting there.
Rolling on a proper tire certainly changes the gearing thoughts in my mind.
Switched out some Ritchey 40 cross tires for some cheap from a friend Kenda 2.2s.
Wind and being sore today... + fat tires.
Running 32/18 SS today. Will see how it feels 32/19 fixed next week when I get the muck out of my lungs.





Have a disc rotor and parts... will work on that next week.

[Slowerthensnot]

Nice

[bmike-vt]

Sticky and Slow – the Tale of a Star Nut, Fat Tires, and a Sealed Bearing Race Stuck in a Hub.
November 9th, 2009

I know larger tires work against you when comparing rolling resistance, gear calculations, and overall effort… but since putting on the Kenda Nevegals I’ve felt like I’ve been riding with both front and rear brakes dragging. Sure, they certainly are not the 28s I ride on the IF, nor the 35s I used to ride on the CrossCheck, nor even the 42s I started with on the Soma…
Yes, I know they are not that wide...

This morning I heard a chirping sound. Damn! I was dragging a brake. Cool. I can fix that. Except that even with the brakes wide open I still heard it. Then I spun the rear wheel by hand. I made it about 1/4 revolution before stopping. Bearings must be mal-adjusted. Picked up the appropriate sized cone wrenches, spun off the single speed side, and loosened. Nope. Bearings were shot.

Off to the internet. Plenty of instructions on removing sealed bearings from Surly hubs. These have served me for 3 winters… rain, snow, salt, dirt roads – pretty much everything. Pulled the axle. Tap tapped the bearing as instructed in lieu of a fancy bearing puller. The innards popped out and I now have a collection of tiny steel balls rolling around on the garage floor.

Which leaves the problem of how to get a sealed bearing race out of a hub shell. Dirt Rag provided the answer. I opted to not hammer the star nut from the opposite side, and instead applied a bit of finesse (in short supply at this moment in my caveman actions thus far) with a bolt and socket. Success. Now to wait for some new bearings – and to let the LBS pull the opposite side.















Hope this helps someone...!

[Slowerthensnot]

Nice trick!

[rocky rode]

What a great idea, Mike.    The star nut might also work to remove outboard BB bearings to replace with Enduro bearings, I'll be playing with this idea!

Bike looks great!