Sizing advice on a 26" Long Haul Trucker flat bar build?

[Northern_Monkey]

Hello,

I'm looking to buy a 26" Surly Long Haul Trucker frame and forks as a commuter/tourer for my wife. This is to get get proper rack mounts, down tube cable routing to fit a kiddie seat in the future and for it to be in a nicer colour. Open to other frame set suggestions as long as it has 26" wheels.

I need a bit of sizing advice though as it has to be a flat bar set up. She's 5'8" and currently riding a NOS 90s Raleigh mtb with modern parts and new Deore/Sputnik wheels.

Would the 54cm be the right size based on her current set up, if it had say a 110mm or 120mm stem with mtb bars and not drops?

Also wondering if there is clearance to fit 2.0" marathons and mudguards?

Thanks

Current set up:


Actual top tube (c-c) - 565mm
Effective top tube - 580mm
Seat tube (c-t) - 500mm
Stand over with 2.0" tyres - 780mm
90mm +5 deg stem, 60mm of spacers under stem and zero rise bars
Wheelbase 1080mm
Chain Stays 425mm
Seat stays 470mm
Headtube 125mm
Fork length (a-c) 410mm

54cm Long Haul Trucker:
Seat Tube Length (c-t) 540mm
Top Tube Length (c-c) 549.7mm
Effective Top Tube Length (c-c) 555mm
Head Tube Angle 71.0˚
Seat Tube Angle 73.0˚
BB Drop 47mm
Chainstay Length - 460mm
Wheelbase - 1064mm
Standover Height - 792.4mm
Head Tube Length - 182mm
Fork Length - 376mm
Fork Offset - 45mm
Stack - 568.3mm
Reach- 379.4mm

[Heltor Chasca]

I'm not really qualified to answer your bike fit question, but I can help with tyre clearance. From Surly:

'Tire Clearance26˝: 2.1˝ with or without fenders; 700c: 42mm with fenders, 45mm without fenders Individual tire and rim combos affect tire clearance.'

[Brucey]

Fundamentally the idea is that there is a 'correct' position for your backside vs the BB and then the handlebars vs the saddle. The correct backside position varies with the rider (lots) and the application (to a lesser extent). The 'correct' handlebar position varies a lot with both the build and preference of the rider as well as the application.

As you will have noticed some MTBs can have a rather long tp tube in the small/medium sizes. This may or may not result in a 'real' change in the reach depending on the seat tube angle. I would suggest measuring the angles on the current frame from a photograph, but the one you have is clearly taken using a camera phone with a very short focal length lens and this means all the angles will be distorted. If you want to take a useful photo it needs to be taken from further away using either a digital zoom or a longer focal length lens.

Although you have a lot of measurements there, I'm not sure there are enough to allow an exact comparison to be made as yet. The dimension that is most likely to be different in this case (in a rider-fitting-the-bike kind of way) is probably the 'reach' dimension. This is usually defined as the distance from a vertical dropped through the BB, to the top of the headset. It is easy enough to make a rough comparison but a more exact one will require that you also know the height of the headset vs the ground or (better) the BB.

Having said all this I suspect that there will be a significant difference in the stack and reach because the Raleigh MTB frame is designed for offroading and many of them were also designed so that you can perhaps go racing too, which (at that time) meant a long and low riding position, reach-wise most like the position on the tops of a road bike. A common problem with these frames is that leisure riders can't get the reach short enough unless a very short stem is used, and fitting dropped bars is pretty much impossible. By contrast the LHT is intended for touring and also to accept either flat or dropped bars. These things mean that the BB height is probably going to be lower and the stack/reach are liable to be both higher and shorter, all things being equal. Some frames are designed to accept a suspension for and others are not, too. So assuming the riding position is about right at present, I'd expect you to need a longer stem and/or a slightly larger frame size on the LHT.

BTW a 26" wheeled LHT is a nice frame and like you say the braze ons are all there. But if you are on a budget there are quite a few '80s and '90s steel MTBs out there which have all the right braze-ons already and will build up into a flat barred tourer quite nicely. Quite a few of these machines have DT cable runs (common the late '80s) or side-mounted TT cable runs, which don't preclude the fitment of a kiddie seat in many cases.

cheers

[hoppy58]

LHTs come up quite big...I built this for my 5'3" wife...it's a 46cm...if that's any help?

EDIT...just seen She's 5'8"...I'm 5'8" aswell and used to have a 52cm LHT, however I always felt it was a bit too big and a 50cm would have been better. Bearing in mind that with a child seat you won't want a high standover (to mount the bike), I would think a 54cm would be way too big..

[Northern_Monkey]

@Heltor - Cheers for that, glad they chose sensible clearances

@Brucey - That is a detailed reply!

You are spot on about the photo, I will try and get a better one with a proper camera. Good point on the reach, that was something I should have thought about.

I did consider an old MTB frame to use from eBay, unfortunately the cost of a new threadless fork and getting them powder coated a matching pretty colour meant there wasn't a huge amount saved.

Well it does sound like a bit of a gamble, if the standover is OK the the reach/rise should be adjustable within a certain range.

[iandriver]

I have 26 * 2.0 Marathon Supremes and mudguards on mine. There is tons of clearance.

[Heltor Chasca]

BTW: I am 5'5" and have a 50cm Surly DT (same frame geo) The TT was too long so I fitted a short stem and a zero offset seat post. I could sit on it all day and I do [emoji4](I am not the only one to observe that the LHT/DT is too long)

[Northern_Monkey]

Thanks for the general sizing advice, I will bear that in mind in terms of longer top tubes and stand over height.