Just about to click buy on a nice, shiny new Jeffsy 27 and thought I’d take a closer look at the geometry. I’m normally not that bothered as I figure bike designers know far more than me, and I’ve ridden a size medium in every bike I’ve ever owned or hired so not expecting any surprises.

Who in their right mind at YT thought it was a good idea to put an 18″ seat tube on a medium sized bike?! In the era of 170mm dropper posts and every other company speccing 410mm (16″) seat tubes. And not only that but brag about the fact they’ve extended the seat tube by 40mm!!

I reckon I’ll be able to get a 100mm dropper to fit. Just. Possibly (short legs and long back).

Is there any more to this than stupidity – I wasn’t sure if the carbon layup is fragile in this area of the frame so they had to increase seat tube length to reduce the risk of snapping?

I’m 5’6″ with a medium (29) Jeffsy. 150mm Reverb slammed apart from about 3mm.

Thanks- seattube on the 29er is 10mm shorter. I’ve measured my current bike and I know 100mm will be tight.

Bird, Transition etc speccing 410 seat tubes so 450mm seems bizarre

Edit- basically BB (middle) to seatrails has to be a 625mm

All YT’s are the same! I’m a medium in most bikes but would be a large Capra. The Capra has a 480 seat tube compared to 430-400 in everything else i’ve looked at.

Yeah same this basically prevented me from buying a jeffsey

How tall are you OP?

I was concerned about seat tube length but it’s not been a problem. I’m 5’9″ with short legs (30″ leg jeans) and 150mm dropper is all good on a medium Jeffsy 27.

I would say Bird and a few others are the exception still at this stage, friend bought a vitus last year for example and seattube was about 3inches bigger than my Aeris.

How tall are you OP?

I was concerned about seat tube length but it’s not been a problem. I’m 5’9″ with short legs (30″ leg jeans) and 150mm dropper is all good on a medium Jeffsy 27.

That’s interesting… I’m 5’6″ but 28″ inseam. As above, I need a BB (middle) to saddle rail measurement of 625mm. Don’t suppose you’d be kind enough to measure yours when you get a spare minute this week and drop me an email (in profile)?

I measured my 100mm drop Reverb at 195mm from the point it hits the seatclamp to the saddle rail. So if I need a total length of 625mm that leaves me with a max seat tube length of 430mm, and the Jeffsy is bl**dy 450mm!

I’d be happy with a 100mm drop tbh, although 125mm would be better. A while ago I figured out how to limit the extension of a Reverb by 5mm but that was an externally routed model – the internal routing ones are different.

It’s been highly documented on every single corner of the interweb, so I’m surprised you haven’t worked out yet, that you size up with YT

It’s been highly documented on every single corner of the interweb, so I’m surprised you haven’t worked out yet, that you size up with YT

I think he already is looking at a Medium being 5’6.

Erm yes I thought that was fairly clear!

One should now be looking elsewhere for a bike that would fit, then try on for size, test ride and buy.

😛

What are the units of measurement that medium comes from?
It’s a word not a measurement.

Buy a small. you are a small person.

I’m 5’5 1/2″ & I ‘m on a small with the 125mm dropper as far into the frame as it will go & I just get away with it, must have very short legs I guess.

Buy a small. you are a small person.

I’m 5’7 so smallish but with shorter legs and a longer torso. The small Jeffsey has a reach of 410mm which is too short in my opinion for anyone over 5’6 who wants to run a 40 or 50mm stem.

My old bike had 415mm reach and 430mm seattube which allowed me to run a 125mm reverb with about 10mm spare out of the seatube. The 450mm seatube on the jeffsey rules that out which is a real shame. Anyone fancy taking a hacksaw to the seatube of their new bike 😉

o/p remember that different saddles have different heights. I swapped from a Specialized Henge to an SDG saddle and had to drop the seat post a good 10mm to compensate.

I cut down the seat tube on my capra

It’s an issue more generally, specially for the shorter-legged. I might just be able to fit a 150mm dropper in an 18″ seat tube, but the fully up position might be a wee bit too high for me. If I go for a large size frame with a 19″ st, a 125 is pushing things.

Then again, I’m not sure I need more than 125mm drop.