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pengyou 11-01-07 11:30 AM

FB and speed
 
How does an average folding bike do at 25-30 mph? How durable are they?

law4jba 11-01-07 11:53 AM

I've had my fixed gear swift up to 30 mph. Besides a bit of bouncing in the saddle at the elevated cadence, the bike handled fine.

Bacciagalupe 11-01-07 01:05 PM

The "average" sub-$700 folding bike is set up with hybrid geometry, somewhat upright position and medium-width tires. You'd have to work pretty hard to hit 25 on the flats. Durability and component quality is a little less than a non-folding bike IMO.

Once you hit $700, you're typically dealing with stiffer frames, flexible positions, drop bars, better gearing options, and so forth. It'd be pretty close to an entry-level road bike. Durability is pretty good.

If you go above $1500, there isn't much performance, durability or quality difference between a folder & a road bike; the folder will probably be a little less comfortable.

One caveat: 20" wheels have a lot of oversteer, so they are trickier on the descents. I feel far more comfortable bombing down a hill at 45mph with my 700c cross bike than I do at 35mph on my folding bike.

14R 11-01-07 04:06 PM

I have a ard time keeping my 16" wheeled Brompton above 21mph for more than a few minutes. I cannot blame all on the bike though...

Pine Cone 11-01-07 04:36 PM

Quote:

Originally Posted by pengyou (Post 5558510)
How does an average folding bike do at 25-30 mph? How durable are they?

How does an average bike do at average speeds of 25-30 mph? How durable are they? I would hate to ride most of the average bikes sold in any country. I would guess that the average bike in the US costs under $250 and I wouldn't feel safe riding it at higher speeds or longer rides without major modifications.

The average folding bike is similar to the average non-folding bike. Neither is particularly great at higher speeds, and average components are pretty average. If you are just talking about average speeds of 10-15 mph and zipping down a hill at 25+ mph either will do just fine. My DT VIIIH is very stable and feels very safe at 30 or 35 mph. Now that I have a longer stem on my DT Mini it does fine at 25-30 but with the stock 2006/2007 stempost higher speeds were a bit scary.:eek:

Comparing $$ spent, you can get a better bike for the money with a non-folder. For the above $400 bikes, you would probably have to spend $100-$300 more for a good folder vs. a good similarly-equipted standard road bike.

For high performance bikes you have lots more choices in non-folders, but you can get pretty nice folders if you are willing to pay for it.

The target market for folders tends towards durability and affordibility. Personally I wouldn't want a carbon-framed folder since it wouldn't fare well getting knocked around in the back of my car on on a crowded bus or train compartment. If you are willing to spend more than about $300 there are plenty of durable folders that will do fine for short distances of 25+ mph. If you want to ride long, fast hard miles you would do better with a $1000 standard road bike or a $1200+ folder from Birdy or Bike-Friday or Dahon.

SesameCrunch 11-01-07 04:36 PM

If you need to go 25-30 mph regularly, why do you need a folding bike? There's no substitute for a good road bike at those speeds IMHO.

pm124 11-01-07 09:17 PM

Quote:

Originally Posted by SesameCrunch (Post 5560295)
If you need to go 25-30 mph regularly, why do you need a folding bike? There's no substitute for a good road bike at those speeds IMHO.

??

Pengyou shensheng--

Small wheeled bikes are fast. Contrary to conventional wisdom, they are possibly a bit faster with stiff suspension on board since it may decrease rolling resistance. Most speed records were set on small wheels. (And, yes, if you look them up, in a variety of conditions!)

I find my small wheeled suspension folder to be possibly faster (still not sure about this) and definitely more comfortable and thus less tiring than a road bike on long rides. But it depends on your needs.

If you are taking it on crowded public transport, you'll need something like a Birdy. This is a fast bike that eats up fully loaded long tours on harsh roads, but is not appropriate for fast group rides if you are a puller and sprinter. (I do them, but I'm a sitter and spinner.) Also in ths general size, the Dahon Mu SL and Jetstream XP are fast bikes. Incremental improvments may one day render Dahon king, but for now the frame hinge and weaker stem are major concerns. While you can put 40,000 hard miles on a Birdy without a worry, Dahons cannot yet take that kind of use. They are priced about in the same range as full size bikes, with a SRAM X9/American Classic equipped bike coming in at $900US.

If you are putting it in your closet, a Moulton (separable), Airnimal, or Reach might be more appropriate in the tight suspension category. A Swift is a very fast, cost-effective, and relatively light bike with a harsher ride, but not too different from a road bike with respect to harshness and should be custom ordered with drop bars, etc. (Only been on one once.) If you are a steel frame person, there is nothing like a custom, hand built Bike Friday Pocket Rocket Pro or Moulton. These bikes really ride well, but are not as easy to take into trains, planes, cafes, etc. The folded size is big and it takes a while to fold them.

Check out: http://birdy.yeahbike.com/ for the Birdy (2008 Speed model available in Europe is Tune equipped and a bit lighter. Japanese models are available with Ti frames.)

http://www.bikefriday.com/node/1591 for the Pocket Rocket

Of course, there are doubters out there, but I wouldn't ride a road bike.

The bikes I lust after are the new 8Kg Reach and the Bridgestone Moulton, though I haven't ridden either.

pm124 11-01-07 09:24 PM

This is the fastest folder you can possibly get: http://tw.video.yahoo.com/video/play?vid=1292778

jnb-rare 11-01-07 09:44 PM

Perhaps the OP is thinking about a folding, electric conversion? I notice some posts in the e-bike forum.

Either that or regular peloton riding. Or maybe Pike's Peak downhill?

Anyway, the kind of bike you might PEDAL to 25 or 30mph could be different than the kind of bike you'd SIT ON while going 25-30mph. Downhills with the Stelvios on my MU SL, 25-30mph (40-48kph) definitely feels more squirrely than my old mountain bike with wide slicks -- especially when the road surface isn't so good.

spambait11 11-01-07 09:51 PM

Quote:

Originally Posted by pm124 (Post 5561990)
Small wheeled bikes are fast. Contrary to conventional wisdom, they are possibly a bit faster with stiff suspension on board since it may decrease rolling resistance. Most speed records were set on small wheels. (And, yes, if you look them up, in a variety of conditions!)

What do you keep referring to when you say this? The Varna Diablo II?

Fear&Trembling 11-02-07 07:06 AM

Most folders will handle 25 -30 mph fine - more appositely though, will your body?

At speeds above 40mph, I much prefer 700c wheels beneath me.

SesameCrunch 11-02-07 07:13 AM

Quote:

Originally Posted by pm124 (Post 5561990)
Small wheeled bikes are fast. Contrary to conventional wisdom, they are possibly a bit faster with stiff suspension on board since it may decrease rolling resistance. Most speed records were set on small wheels. (And, yes, if you look them up, in a variety of conditions!)

The question is about folders, not small wheel size.


Quote:

Originally Posted by pm124 (Post 5561990)
I find my small wheeled suspension folder to be possibly faster (still not sure about this) and definitely more comfortable and thus less tiring than a road bike on long rides. But it depends on your needs.

It's completely illogical to think that a folding bike with suspension is faster than a racing oriented road bike. The additional weight of the folding mechanisms and suspension adds at least 5 pounds to a bike. The rear suspension sucks up energy when pedaling. There's no folding bike in the world that could match up with a 16lb racing rig.

Foldable Two 11-02-07 12:47 PM

Hey, I did 26.3 MPH on my 2005 Dahon Boardwalk D7 on a long smooth downhill in the 2007 Portland Bridge pedal on Tioga Pool Comp 1.75" slicks.

That was the limit of 7th gear. The ride was very smooth.

I doubt the friends we sold the D7s to yesterday will get up to that speed. (My wife freaks-out at any down hill, whether on the old Dahons or her new Pocket Crusoe.)

awetmore 11-02-07 01:59 PM

Quote:

Originally Posted by Bacciagalupe (Post 5559071)
One caveat: 20" wheels have a lot of oversteer, so they are trickier on the descents. I feel far more comfortable bombing down a hill at 45mph with my 700c cross bike than I do at 35mph on my folding bike.

What do you mean by oversteer? In car terms this would mean that the front wheels are sliding forward instead of carrying you through the turn. Pushing a bike to that limit usually involves a lot of crashing.

I don't think that most folding bike designers understand bicycle handling very well. They tend to copy road or mountain bike head tube angles and fork offsets. Doing so results in bicycles with very low trail, so very little natural stability. Folding bikes should have reduced fork offset. I like low trail bicycles (and my full size bicycles have lower trail than almost all production bikes made today), but you can go too far.

alex

pm124 11-02-07 02:05 PM

Quote:

Originally Posted by SesameCrunch (Post 5563163)
The question is about folders, not small wheel size.




It's completely illogical to think that a folding bike with suspension is faster than a racing oriented road bike. The additional weight of the folding mechanisms and suspension adds at least 5 pounds to a bike. The rear suspension sucks up energy when pedaling. There's no folding bike in the world that could match up with a 16lb racing rig.

Folders are definitely heavier, but that doesn't make any difference on a flat. It also doesn't have much to do with suspension, which can come in at a couple hundred grams in Pantour hubs or a simple elastomer set up. But, yes, on climbs you will pay lugging around that extra weight.

The idea is that suspension causes less tire sidewall deformation on uneven surfaces. Smaller tires hit the road at a more acute angle causing increased sidewall deformation. However, this is more than offset by a smaller volume of air in the tire. (Remember old PV = nRT?)

Another factor: When you hit a bit of uneven road, it pushes back, and will push back harder against a stiffer tire (e.g., one on a small wheel). Here, too, the suspension will potentially help you get over that deformity.

If you ride the bike properly (e.g., spin in a circular motion, lifting and pushing at the same time), then it will not soak anything up. Thus, another way that it makes you faster is to teach proper riding style!

How does a folder slow you down then? 1) It is heavier, 2) one cannot pull on the handlebars (unless it is a Moulton), 3) there is no diamond, thus it is less stiff. I do fine in a peleton until we hit the uphill. Probably more of a body fat problem than a bike problem, but I can't get out of the saddle to compensate.

pm124 11-02-07 02:15 PM

Quote:

Originally Posted by spambait11 (Post 5562176)
What do you keep referring to when you say this? The Varna Diablo II?

Most of the historical HPV speed records, including the Moulton: http://www.ihpva.org/hpva/hpvarech.html

Look at this insane thing John Howard took to 152 MPH: http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm

Here is the Moulton: http://www.treehugger.com/files/2004/11/bike.php which is perhaps even stranger.

pm124 11-02-07 02:25 PM

Quote:

Originally Posted by Fear&Trembling (Post 5563142)
Most folders will handle 25 -30 mph fine - more appositely though, will your body?

At speeds above 40mph, I much prefer 700c wheels beneath me.

At speeds above 40mph, I much prefer 12" wheels beneath me.

http://www.rmtbristol.org.uk/tgvV150_thiaucourt.jpg

But on I bike, I'd have to go with nice fat 26" wheels.

spambait11 11-02-07 02:27 PM

Quote:

Originally Posted by pm124 (Post 5565567)
Most of the historical HPV speed records, including the Moulton: http://www.ihpva.org/hpva/hpvarech.html

Look at this insane thing John Howard took to 152 MPH: http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm

Here is the Moulton: http://www.treehugger.com/files/2004/11/bike.php which is perhaps even stranger.

I see. So SC is right: you're differentiating between folding bikes vs. smaller wheels in general.

pm124 11-02-07 02:29 PM

Quote:

Originally Posted by spambait11 (Post 5565625)
I see. So SC is right: you're differentiating between folding bikes vs. smaller wheels in general.

Yes. I'm still pre-verbal sometimes. Though there shouldn't be much of a difference if the folder were built properly (e.g., no frame hinge).

Fat Boy 11-02-07 03:19 PM

Quote:

Originally Posted by awetmore (Post 5565483)
What do you mean by oversteer? In car terms this would mean that the front wheels are sliding forward instead of carrying you through the turn. Pushing a bike to that limit usually involves a lot of crashing.

alex

Actually, in car terms it's the other way around. The rear sliding towards the outside of the corner and the front continuing on the path that they were pointed until the car spins. Regardless, I'm a bit confused by the term as well when attributed to a bicycle. Perhaps he just meant that the steering response was quicker.

Fat Boy 11-02-07 03:21 PM

Quote:

Originally Posted by SesameCrunch (Post 5563163)
It's completely illogical to think that a folding bike with suspension is faster than a racing oriented road bike. The additional weight of the folding mechanisms and suspension adds at least 5 pounds to a bike. The rear suspension sucks up energy when pedaling. There's no folding bike in the world that could match up with a 16lb racing rig.

Ya, but he likes his kool-aid and has been repeating this same basic message on every thread that's even remotely related. I think he's going to enter an A-bike in the TDF next year and clean up.

Simple Simon 11-02-07 04:02 PM

Quote:

Originally Posted by SesameCrunch (Post 5563163)
It's completely illogical to think that a folding bike with suspension is faster than a racing oriented road bike. The additional weight of the folding mechanisms and suspension adds at least 5 pounds to a bike. The rear suspension sucks up energy when pedaling. There's no folding bike in the world that could match up with a 16lb racing rig.

I'm with SesameCrunch & Fear&T on this. I know as this is a folding / small wheel forum so we tend to get enthusiastic about these, especially for multimodal work and travelling, which is what they are designed for, but for longer rides I'll take the 700c thankyou.

Back in the days, I once disabled the suspension on an early moulton - guess what - it was faster ! ... especially on climbs (without ol' Bob).

SesameCrunch 11-02-07 07:06 PM

Quote:

Originally Posted by Simple Simon (Post 5566145)
I'm with SesameCrunch & Fear&T on this. I know as this is a folding / small wheel forum so we tend to get enthusiastic about these, especially for multimodal work and travelling, which is what they are designed for, but for longer rides I'll take the 700c thankyou.

Back in the days, I once disabled the suspension on an early moulton - guess what - it was faster ! ... especially on climbs (without ol' Bob).

Having 5 folders in my current fleet, I understand being enthusiastic about folders - I've been guilty of that myself sometimes :o. Let's not even talk about the obscene amount of time I spend on this Forum :eek:!

Simple Simon 11-03-07 06:13 AM

Quote:

Originally Posted by SesameCrunch (Post 5566931)
Having 5 folders in my current fleet, I understand being enthusiastic about folders - I've been guilty of that myself sometimes :o. Let's not even talk about the obscene amount of time I spend on this Forum :eek:!

Its an illness .. 12 point plan anyone :D

Bacciagalupe 11-03-07 07:23 AM

Quote:

Originally Posted by awetmore (Post 5565483)
What do you mean by oversteer?

"Excessively responsive handling." I don't own a car, so I have no idea how that term would apply there. :D


Quote:

Originally Posted by awetmore
I don't think that most folding bike designers understand bicycle handling very well. They tend to copy road or mountain bike head tube angles and fork offsets....

That may be the case, but unless you're drastically modifying the geometry, small-wheeled bikes are less stable and turn more responsively than 700c bikes.

For example, my Swift has a wheelbase of 1010mm, which is slightly longer than my cross bike; it also has a straight fork. The Swift has excellent acceleration (with the right tires, that is ;) ) and is better at dodging obstacles; the cross is much more stable, descends better, handles loads better, and handles bumps better.

For general riding, it's not a big deal. For some uses, e.g. urban riding, it's a selling point. For touring, long rides, group rides, fast rides and technical descents, handling is definitely one factor among many to consider.


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