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Here's Why the Bridgestone Grandtech is an Interesting Bike

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Here's Why the Bridgestone Grandtech is an Interesting Bike

Old 04-24-21, 11:44 AM
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Here's Why the Bridgestone Grandtech is an Interesting Bike

THIS ... is a 1984 Bridgestone Grandtech GR-27:



I believe it is one of the coolest folding bikes ever built. Back in the eighties Bridgestone made some really cool and weird stuff: the Blouson, the Montecarlo and this Grandtech.

According to The Folding Cyclist the design was conceived by two Bridgestone engineers, Ritsuo Nishimura and Nobuaki Shimada and patented in 1983. It won the Good Design Award in 1984 and appeared in the Bridgestone catalog from '86 to '88.

In this thread, I am going to show you all of the Quirks and Features of the original Bridgestone Grandtech.



I found the bike courtesy of a thread on another forum on the Italdesign Bridgestone Montecarlo. Thinking I'd like me one of those, I started a search but instead of a Montecarlo this Grandtech popped up. For sale, near me.

I knew of the bike, as I have a copy of Michael Embacher's Bikepedia:

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Old 04-24-21, 11:46 AM
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The crank set is a single ring affair, a Sugino No. 3. The pedals are really cool: pull the what looks like the dust cap and it folds flat:



The rear mech is a SunTour AR, defended by a chromed bracket, which seems like a good idea if you're going to be schlepping this bike around on buses and trains. More interestingly, the shifter cable is plastic-covered. I only discovered this when I replaced it with a new cable. In hindsight I shouldn't have replaced it, as it still moved pretty smoothly:

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Old 04-24-21, 11:51 AM
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The hubs are from Sansin, and the freewheel is a SunTour Perfect:




Shifts are performed with the aid of a SunTour Power Thumb Shifter. It works as well as it sounds:

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Old 04-24-21, 11:57 AM
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For when you need to warn other road users of your eminent approach, there is an official Bridgestone bell:



When you need to turn the handlebars for transport, no tools are needed. There is a convenient lever that does the job:




Lowering the saddle is just as easy:

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Old 04-24-21, 12:00 PM
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This is what it looks like when folded:

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Old 04-24-21, 12:05 PM
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The bike came to me with what looks like the original documentation: an accessories catalog, a warranty booklet, the instruction manual, a booklet on cycling safety and even the original price tag.



The straps are meant to secure the bike during transport, according to the instruction manual:

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Old 04-24-21, 02:02 PM
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Wow, that's so cool! The golden age of Japanese mechanical engineering.
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Old 04-24-21, 10:16 PM
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Dang, that’s cool
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Old 04-25-21, 05:26 AM
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I think that is the coolest post I'll see today.
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Old 04-25-21, 08:34 AM
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Fascinating.

Curious - when folded, will the serrated locking assembly lock the two halves in their folded state? Can't tell from the photos, and I'm always curious about the amount of effort put into maintaining the folded state of any given folded bike.

-Kurt
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Old 04-25-21, 11:53 AM
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You're making me hate myself more and more for not trying to find one while I was in Kyoto a couple of years back, too much going on and it didn't occur to me at the time. Oh well, there may be a return visit in a year or two and if so...
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Old 04-25-21, 12:04 PM
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With the manuals, a good way to brush-up your Japanese.

Another unique bike brought to us by @non-fixie.

Was it distributed outside Japan? Never ever seen even a pic.
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Old 04-25-21, 12:24 PM
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That's pretty cool!

I'm looking at it, though, and wondering why the seatstays are bolted onto the rear dropout... Is it just for some further compact disassembly? Maybe I'm missing something. Looks, though, that in the folded state it's all still bolted together.
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Old 04-25-21, 12:30 PM
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Originally Posted by Wildwood View Post

Was it distributed outside Japan? Never ever seen even a pic.
Smaller-wheeled versions were distriibuted in Asia from 2013 onward, I've read, but at the time? I don't think so. Not on any sort of scale, anyway. This one was sold by a local shop in Tilburg, Holland. No clue yet how they managed to lay their hands on it.

The only reason I knew it existed was that it was in Michael Embacher's collection, and I have his book in my bathroom.
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Old 04-25-21, 02:21 PM
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A folding lady ... no, serious, lovely bike!
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Old 04-25-21, 03:58 PM
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The bike is fitted with nutted axles, and one quirk I came across, as I was servicing the bearings, is that the front wheel nuts are 14mm, while the rears are 15mm. Luckily a standard open wrench comes in 14-15mm ... which I'll have to carry along to be able to replace an inner tube.


So, how does it ride?

After replacing the gummed-up grease, the 22mm 35-year old Hutchinson tires and the too narrow (for mrs non-fixie) saddle, we took it for a ride.



It was supposed to be a short shakedown ride, as we wanted to watch La Doyenne as well, but we stayed out for over an hour. She liked the way it rides: very much like any lightweight sports bike. The only thing that requires further investigation are the semi-flat handlebars. The offer only one hand position, which makes them less attractive for longer rides.

All in all, it got a thumbs-up from its new owner.
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Old 04-25-21, 04:05 PM
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Originally Posted by cudak888 View Post
Fascinating.

Curious - when folded, will the serrated locking assembly lock the two halves in their folded state? Can't tell from the photos, and I'm always curious about the amount of effort put into maintaining the folded state of any given folded bike.

-Kurt
According to the picture in the manual the bike is not locked into its folded position (the lever is in the "up" position). Apparently that's what the two straps are for.
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Old 04-25-21, 07:15 PM
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Very nice! That's possibly the most elegant folding bike I've ever seen.
Not surprised, Bridgestone was always quietly innovative, and very, very Japanese.
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Old 04-25-21, 07:42 PM
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Nice design, but I'm not exactly digging the way the seat stays are attached to the rear drop outs. It looks like an M5 nut and bolt, and I'm no engineers, but it seems like a lot of stress to put on two little bolts.
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Old 04-26-21, 06:04 AM
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wonderful thread non-fixie ; thank so much for sharing this mount!

me too has been wondering anent the reason for the bolt-on seat stays

have you figured it out?

you may find steerer to exhibit the Bridgestone keystone symbol


-----
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Old 04-26-21, 07:11 AM
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Bolt-on stays would have allowed the BB/chainstay section to get compacted quite small, if disassembled. Perhaps a trick for long-distance breakdown/touring? @gugie, any ideas? I remember you mentioned a fender mod popular in Japan for touring bike transportation.

-Kurt
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Old 04-26-21, 09:51 AM
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Originally Posted by DiegoFrogs View Post
That's pretty cool!

I'm looking at it, though, and wondering why the seatstays are bolted onto the rear dropout... Is it just for some further compact disassembly? Maybe I'm missing something. Looks, though, that in the folded state it's all still bolted together.
My thinking is that the bolts are not meant for disassembly but to provide a couple of pivot points that allow the "seat tubes" to un-clamp for folding. There would be too much tension on the clamp if the rear triangle were solid.
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Old 04-26-21, 07:37 PM
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Originally Posted by juvela View Post
-----

wonderful thread non-fixie ; thank so much for sharing this mount!

me too has been wondering anent the reason for the bolt-on seat stays

have you figured it out?

you may find steerer to exhibit the Bridgestone keystone symbol


-----
Originally Posted by cudak888 View Post
Bolt-on stays would have allowed the BB/chainstay section to get compacted quite small, if disassembled. Perhaps a trick for long-distance breakdown/touring? @gugie, any ideas? I remember you mentioned a fender mod popular in Japan for touring bike transportation.

-Kurt
Originally Posted by non-fixie View Post
My thinking is that the bolts are not meant for disassembly but to provide a couple of pivot points that allow the "seat tubes" to un-clamp for folding. There would be too much tension on the clamp if the rear triangle were solid.
All I can add is

@cudak888, the fender mod you're thinking of is commonly referrered to as part of the "rinko" solution, which allows a standard bike to be broken down fairly quickly into a carrying bag of a certain size, which allows said bike to be brought into a Japanese train without extra charge. It's handy when boxing and shipping a bike with fenders.

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