Touring - what size surly long haul trucker?

should i get the same size touring bike as my roadbikes?

all my roadbikes have a effective top tube length of 515mm-520mm. should i get the same effective top tube length for a surly long haul trucker?

yes, if you're comfortable on that ETT on your roadie, that would be exactly how I would (and did) choose a tour bike.

yes

you should always make $1000 purchasing decisions based on advice from anonymous internet posters, it's the best way

seriously - if you intend to use same seatpost, saddle, stem, bar and levers - it should fit the same, reach-wise.

the resulting size / seat tube will be shorter - after adding bigger tires you will end up with about same standover height

note - tourists normally favor a more upright position than the usual road bikes - something to consider in your size choice.

yes

you should always make $1000 purchasing decisions based on advice from anonymous internet posters, it's the best way

seriously - if you intend to use same seatpost, saddle, stem, bar and levers - it should fit the same, reach-wise.

the resulting size / seat tube will be shorter - after adding bigger tires you will end up with about same standover height

note - tourists normally favor a more upright position than the usual road bikes - something to consider in your size choice.

i have noticed the more upright position of tourists. i have also noticed that most touring bikes have teeny tiny short stems, that are angled up...which leads to a more upright position. roadies like me usually have long stems, angled down.

i have noticed the more upright position of tourists. i have also noticed that most touring bikes have teeny tiny short stems, that are angled up...which leads to a more upright position. roadies like me usually have long stems, angled down.

A lot of tourists do tend to have the stems up and ride more upright as well. I have my bars on my roadie a good 10 cm lower than my seat and my tourer at least 5 cm lower. That is just what makes me comfortable. It's different for everyone. Just like bar end shifters... I can't stand them. I do understand other people liking them though. I run a 100 mm stem/flipped just like my roadie. It's still like jumping on a beach cruiser compared to the TCR.

Test ride will decide the rest.

If you are buying a Surly LHT then be aware that Surly measure their frames differently from everyone else. They measure frame size from to the BB centre to below the top of the seat tube so their sizes are effectively around 1-2 cm larger than you would normally expect.

Yes, I foremost based my LHT frame size according to ETT lengths of my other road frames. Standover height & seat tube length measurements on the LHT were secondary.

If you are buying a Surly LHT then be aware that Surly measure their frames differently from everyone else. They measure frame size from to the BB centre to below the top of the seat tube so their sizes are effectively around 1-2 cm larger than you would normally expect.

Surly's sizing convention is center of BB to top of top tube/seat tube intersect. This is the most common sizing convention in use today.

Twenty years ago it was center of BB to center of top tube/seat tube intesect.

The shift in conventions is due mostly to move to Al tubing - larger tube diameters caused confusion /fit errors by the older standard.

A minority of makers/sellers use center of BB to top of seat tube. This is a fairly useless sizing convention for obvious reason.

http://www.surlybikes.com/spew17.html

The effective top tube length is most important in regard to getting the correct sized bike. Make sure and look at the geometry chart on the Surly site and be aware that what they call a 52cm bike (the seat tube measured center of bb to top of top tube), for example, has an effective top tube length of 54cm.

all my roadbikes have a effective top tube length of 515mm-520mm. should i get the same effective top tube length for a surly long haul trucker?

Don't think you can go wrong with this approach. The surly site lists effective top tube length in the geometry chart so just go by that dimension regardless of the stated size. You have 50+ mm of variability with stem lengths (probably about 25 mm it either direction from the stock stem), so you should get the bike to fit no problems. I'd hold off on cutting the fork too low (i.e. keep it long enough for 4-5 cm of spacers) until you are certain of the fit.

I notice you are kind of between the 46 cm and the 50 cm sizes, which have 515 mm and 530 mm effective TT respectively. You might consider the other variables like HT angle (70 vs. 71) or crank length if you're getting a complete bike (165 vs 170). One nice thing about shorter cranks is that you're less likely to experience knee pain due to long days in the saddle. But I'd also try to get opinions about the front end handling of the 46 cm with it's quite slack head tube angle.