Educate me on sloping top tubes - or is it just marketing hype?

[veggieburger]

All of my bikes are traditional horizontal top tubes, except one. It has quite a dramatic slope from steerer to seat tube, and that seems to be the norm nowadays. Consequently, I run a longer seatpost to achieve the same sizing as my other bikes. Go into a bike shop and you'll be told about the greater stand-over, reduced weight, added stiffness and so on and so forth. But is this real? Are there advantages to compact frame geometry? My suspicion is it has more to do with reducing the number of sizes that have to be manufactured, but maybe I'm wrong.

[FlashUNC]

Totally reducing the number of sizes at manufacture.

[duff_duffy]

I personally like the way sloping tube looks and as I get older don’t mind that it’s a bit easier to get leg over top tube. How it rides depends on so many other factors (tubing, tires, post, saddle) that I don’t think it matters in this department. I think it is also easier to have fewer frame sizes thus making easier to sell. Add all those factors up and sloping top tubes are a win win in my book.

[mcteague]

Many custom frames employ a sloping TT to get the bars where they need to be and still allow good stand over clearance.

Tim

[Bentley]

I kind of like the shorter seat tube, gives me space to mount a rear camera, rear flashing light that is more difficult on a level top tube bike.

Honestly, I first saw them on the Giants and I was not a fan, now it seems much more common.

Ray

[sparky33]

Agreed. I like that the sloping tt exposes enough seatpost so I can fit a blinky under my saddle pack. Can't do that on a level tt with my saddle height.

[paredown]

Thre's lots of folks around here that know way more than me, but I have a story.

I was skeptical of non-level top tubes--didn't look right, manufacturers just trying to save money etc, etc--until I was in Roberts (UK--as in Chas) helping a friend get fitted for a custom frame.

Sloping top tubes came up; I expressed my geezer-motivated disdain for things new--and then had a good conversation with the young frame-maker doing the fitting.

The short paraphrase--when lugs ruled, tubes had to connect in certain ways, unless you filet brazed. so it turns out that the level top tube was kind of a historical accident, not a natural kind.

Tig then gave you the option to do things differently. Once that is one the table, then you can really think about what you want the bike to do, or be best at, or to fit in a certain way-- What he appreciated was that he could now build frames with taller head tubes (tourists, old gents etc), drop the top tube to give good standover--and end up with a wonderful frame.

I own only one frame with a sloping top tube--but I have dropped my prejudice--or perhaps to say it better, I realize that my prejudice is mainly an aesthetic judgement and in this (as in most things) de gustibus non est disputandum.

[pdmtong]

anyone who mountain bikes doesn't see a sloping TT, they see a bike.

slope is an aesthetic but also reduces mfg inventory and to some extent material

[gary_a_gooner]

Originally Posted by duff_duffy

I personally like the way sloping tube looks and as I get older don’t mind that it’s a bit easier to get leg over top tube.

Wait...when do you have to get your leg over your TT? Isn't getting your leg over the saddle the highest you have to go? You can also mount going over the handlebars, too, I guess.

[oldpotatoe]

Originally Posted by veggieburger

All of my bikes are traditional horizontal top tubes, except one. It has quite a dramatic slope from steerer to seat tube, and that seems to be the norm nowadays. Consequently, I run a longer seatpost to achieve the same sizing as my other bikes. Go into a bike shop and you'll be told about the greater stand-over, reduced weight, added stiffness and so on and so forth. But is this real? Are there advantages to compact frame geometry? My suspicion is it has more to do with reducing the number of sizes that have to be manufactured, but maybe I'm wrong.

If, for fitting issues, you need a certain length head tube and when compared to standover requirements, the result 'may' be a sloping top tube..but for performance, no advantage. Also Giant(I think) started the slopping top tube gig in order to make fewer sizes(S/M/L/XL tye gig) saying that a 'size fit more people so every cm/2cm not required but like threadeless, initilly a way to save $.

[FlashUNC]

http://inrng.com/2012/05/the-ancestor-of-your-bike/

[duff_duffy]

I’m crazy when I ride. That’s me posting a few of my old freestyle bikes, I still do some tricks on my road bike and lower top tube helps

Originally Posted by gary_a_gooner

Wait...when do you have to get your leg over your TT? Isn't getting your leg over the saddle the highest you have to go? You can also mount going over the handlebars, too, I guess.

[juanj]

Another element to consider with the sloping top tube is that by requiring a longer seat post, the design adds compliance to the frame. When I was having a custom bike built for me some years ago, the two builders I was considering explained that that they preferred sloping top tube (at least in my size frame) so there is room for a longer seat post and added comfort.

[Mikej]

Paging 1999, your thread is back...just kidding. Heck back then even mtb bikes had level top tubes. Now it’s just the norm. I prefer a sloper- the frames started getting pretty stiff and I appreciate the extra seat post suspension. I think giant pioneered the S M L sloper size plan to reduce the amount of sizes. Realistically it has contributed immensely to the popularity of cycling today, giving less agile persons more stability and safety over a level top tube. I remember wondering why Kent had a 1.5 degrees slope on a 98 moots vamoots- now I know - Cuz it’s sexy baby, yeah!

[tommyrod74]

Originally Posted by FlashUNC

Totally reducing the number of sizes at manufacture.

This, but I also think (on some frames) more exposed seatpost (especially if 27.2 or 25.4 diameter) smooths the ride a bit.

ETA: next time I'll read all the replies before chiming in