romperrr 

Hello friends,

I'm considering building up a sport tourer into my all city bike. From what I've read, sport tourers differ from their full touring brethren by having slightly more aggressive frame geometry. I'm a big fan of old Japanese steel and settled on something out of the Miyata 600 series. I found a beautiful mid 80's Miyata 618 but when I looked up it's geometry it's the exact same as the much-loved 1000, as seen in the attachment below.

Shouldn't the 618 have a slightly steeper head and seat tube angle and possibly a shorter top tube than the 1000?

I'm looking for something with a slightly more sporty geometry to handle city streets and possible race cross on. Thought the 618 would be a great choice: wide clearance for tires, splined triple butted tubes, and sporty geometry.

Please advise on the geometry question or if possible suggest alternatives. Thank you! For your consideration, some beautiful hand-cut lugs.

Vefer

The 610 has the sportier steering than the 1000, but it still has front and rear rack mounts, canti brakes, and 700 X 34 tires and a triple crank. The early ones are double butted the later ones are triple butted tubes.

romperrr 

Thanks for the reply. Pardon my ignorance, but what constitutes sportier steering? I assumed it would be the frame geometry, which, according to the catalog posted above, is the same for the 618 and the 1000. If you could expound on that I would muchly appreciate it.

Thank you!

WNG

73 degree head and seat tube angles. Shorter chainstays, and fork trail adjusted to quicken handling.

corwin1968

No way I can read that chart.

I'm no expert but I think my Handsome Devil comes close to sport geometry.

Head tube angle 73 degrees
Seat tube angle 73 degrees
BB drop 70mm
Fork rake 45mm
Trail 60mm
Chainstays Variable with range of 43cm to almost 46cm

The front-end geometry is basically that of a road bike while the rear-end geometry is closer to a touring bike. This is practically the same geometry as the 1994 Bridgestone RB-T (with the "T" standing for either "touring" or "triple"....I've heard both). It's not quite as sporty as a road bike and not quite as stable as a touring bike. It has a lot of braze-ons and can take up to 45mm tires. All in all, it's a fantastic city bike and probably a pretty good all-rounder.

The Golden Boy 

I've always felt my Trek 620 feels similar to my 400- I had thought it was the same geometry- but with longer chainstays and a larger fork offset. But there are differences in the angles as well..

I have Trek Touring, Sport Touring and Racing frames- a 1985 620 as a touring frame, a 1986 400 Elance as a Sport Tourer and a 1978 736 as a racing frame.

I'll try a little comparison chart here- the first column will be my 620, then the 400 and the 736.

Seat Tube..............52.1.....52.1.....52

Seat Tube Angle.....73.5.....73.5......73

Head Tube Angle....73........72........71.5

Top Tube...............56........55........54

Chainstay..............47........42.5......41.5

Fork Offset............5.2.......4.5........4.5

Drop.....................7.2.......7.2.........7.7

Wheelbase............105.9...101.1......98.7


The HUGE outlier is the chainstay length- and the Drop in the 736. But interestingly, the Sport Touring geometry is closer to the Racing geometry than it is to the Touring geometry. I would have thought it to be between the Touring and Racing, but closer to Touring.

romperrr 

Thanks for the responses everyone. I've attached a more close up version of the 1000 and 618GT's frame geometry, hopefully it's more legible. It looks like they're exactly the same.

As seen here the 1000 is marketed as a fully fledged tourer, while as seen here, the 618GT is marketed as a sport tourer.

I'm thinking that 618 is really more of a fuller tourer with lower end components and different gearing. Here's a link to the full 1989 catalog if anyone is interested. The frame geometry that I'm referring to is at the end of the catalog.

TiHabanero

romperr, Three weeks ago I finished building up my 85 Miyata 618 into a gravel road grinder. Do not be deceived by the "touring" geometry, it is very sport oriented, just not as light as a typical sport touring bike.


So far I have ridden two track and single track with it and done equally well as my Jake The Snake Kona. It will make a killer cross bike. I have a set of 700x37 tires on it from a Giant Roam (I think they use 40mm tires now on the Roam) and it sticks to the dirt like glue. Can't wait to do some snow riding with it!

Pompiere

As I understood Miyata's marketing, the 1000 was the all out, no holds barred touring bike. The 600 series was the same bike, minus a few features, and the 200 series was lower grade frame and components, but with the same geometry as the higher level touring bikes. I don't own any of them, so it's only my theory. I do have a 310, which was marketed as a sport touring bike. It has a sportier frame geometry, but still comfortable for an all day ride. It also has eyelets on the dropouts for racks or fenders.

due ruote 

I've never ridden any of the Miyata touring bikes, only sport bikes (which were very nice), but based on what you've shown here I'm inclined to agree with your assessment. The distinction seems to be more about marketing than anything else. I just don't see how two splined triple butted frames with identical measurements are going to have different ride characteristics. Perhaps the marketing team felt that by positioning the 618 as a sport tourer, it would be less likely to cannibalize sales of the 1000lt among tourists. Just a wag.

Scooper

Waterford calls this their "Road Sport" geometry, but I've ridden it with rack and panniers from San Francisco to Los Angeles and think it's perfect for light touring. The HTA is 73°, the STA is 72.5°, the BB drop is 75mm, and the chainstays are 432mm long. Fork rake is 42mm resulting in a trail of 59mm.

romperrr 

Due Route, me neither. That definitively answers my question. Thanks.

TiHabanero, that's good to know. If I'll pull the trigger on the 618 I have my eye one, I'll showcase it. Enjoy the snow!