jayhuse

Ok, i know this is a subjective question but just curious how fast can one go on an 8 speed bike such as a Helious P8 or a P8 Dahon ?

I am thinking of buying a folder as a backup bike for myself on commutes but have 18 miles each way to work. As of now I have a really good road bike an wanted a cheaper folding bike as a backup.

The question is if the folding bike is fast enough to do 18, 19, 20, to 25 mph like a road bike ?

I heard all you can expect for a commute with a folder is about 12 to 14mph ??

Thanks

Jay

Wavshrdr

The folders can be as fast as you want. Choose the appropriate tires and keep low on the bars. Lots of folders such as the Swifts and Dahon SpeedPros are very fast. Depending on terrain I can easily average in the high teens on my Swift if I am not carrying a lot of gear and I am willing to keep low on the bars.

At speeds approaching 20mph, aerodynamics become a significant factor. Inherently a folder with good spec components can be virtually as fast as a fast road bike if you go with narrow, skinny tires, have tall enough gears and you are willing to ride in a tuck or on dropped bars. There is nothing that magically makes folders "slower" than a normal road bike and in most instances they will out climb and out accelerate normal road bikes. Theoretically they might give up 1-2% in top speed due to their tires.

The beauty of folders is that you can set them up for a variety of uses and they can do a good to excellent job in many areas. Problem with the Helios and P8 is if you really want to go fast you might need taller gears to take advantage of downhills. A well built lightweight folder can be under 20lbs. and be pretty fast. Problem is most of the ones on the showroom floors don't have anything even remotely approaching high-performance tires on them. Lots of super fast 16" and 20" tires out there.

Guest

Do you have a good idea about which tires may work well to increase speed for a 20 in wheel?

Koffee

jayhuse

I was curious about the bone stock version of the over the counter P8 or Helious or any other type of Folder under 600.00 that would give me a good 18mph or 20mph run within the normal 8 gears sold with the bike.

I see the tires on those are so so. Not mountain bike width but not skinny like my road bike.

If anybody else has a folder that can do some good MPH with it being STOCK let me know. I would also wish it was under 600.00 or so.

Thanks

jay

DaFriMon

Here's an unscientific, single case, comparison. When I started using a stock Dahon Speed P8 to commute on a couple of years ago, where previously I'd been using a fairly fast, drop barred hybrid, my average speed went from around 17 mph to about 15 mph. Okay, almost stock, I'd replaced the saddle and pedals, and put on bar ends. Later I changed out the Schwalbe Marathon tires it came with to Primo Comets, which felt a bit faster, but my actual speeds didn't change much. I'm sure that the fairly low top gear was a factor, as well as the less aerodynamic riding position. On my commute, the few extra minutes each way wasn't a concern. Your experience may be different; you may be a faster rider than me, but don't expect the same speeds you get on your road bike, unless you are ready to do some upgrades, as Wavshrdr mentioned, or get a more upscale model.

By the way, my present commute bike is an 8 speed Bike Friday Pocket Tourist. It has a slightly taller top gear than the Speed, fits me better, and I get a lower riding position on the H bars, the way it's set up. It feels a lot zippier than the Speed, and my actual speeds are a little faster on similar routes. My latest plan for the Speed is to try a drop bar conversion and see how it works out, but this is going to take me a little while to get around to.

Wavshrdr

Scorchers are pretty fast tires. Stelvios are fast too. Depending on terrain Big Apples are very fast. The rougher the pavement, the faster they are relative to other tires. Tioga Comp Pools are fast.

I'd say the fastest of the lot would be the Scorchers NON TR version, the the Scorchers TR, followed by the Tioga Comp Pools and then Stelvios. The Big Apples are surprisingly fast but not in the almost race tire class. However the ride is amazing and on semi-rough pavements they were far faster than my Stelvios.

Marthons are SLOW unless you go for the Racers. Stock Marthons are built like a tank and roll like them too. The heavy duty ones are even worse but you'll probably never get a flat. Tires make a huge difference on these bikes. Tire liners and tubes can make a difference too. Even changing the tire pressure 20psi can make a significant difference.

Guest

Thanks! I find that even keeping my tires pumped to its max helps keep my speed up. This is especially important since I have a lot of hills to deal with for my commute.

Koffee

Wavshrdr

If you use Big Apples, tire pressure isn't such an issue. They roll really well under almost all conditions. They are not a super high pressure tire so don't have to keep them highly pumped up. They are rated to 70psi. At that pressure they seem to ride like a tire with 50psi in them but ROLL like they are 100psi tires. I absolutely love them. I wouldn't race them in long road race but they are a great every day tire that you can even go mild off-roading with. Only the die-hard speed freaks probably wouldn't want them. So for the other 98% of us they are awesome. They are so good that companies make custom "balloon bikes" on the wider version of this tire. They are that popular. I can't find the link but they take Dahons and modify the frames to fit the widest 20" Big Apples. These tires rock!

dalmore

<hijack>

Wavshrdr - what PSI do you run on your Big Apples? I'm running about 80 (I know , I know only rated to 70) and it seems to work great. But I just read the other day that slightly lower than max tire pressure is best for rolling resistatnce. Then I recalled reading something about 65 being the optimal for rolling resistance on the Big Apples but I have not been able to find the reference to confirm my memory. Planning to lower the pressure for my rides this weekend.

</hijack>

jayhuse -Given your price range and desire to have the folder as a backup, you might want to consider the Dahon Cadenza - it's geared high enough to be as fast as you want to go. It's a 26-incher though so it will not folder as compactly but I don't see that as a primary concern for you. It's close to the price point you mentioned too.

Rincewind8

I don't own a Dahon folding bike, but I just looked at the Helios P8 and it has a regular exchangable chainring. So if you don't like the gearing (and can live without the chainring guard) you could always change the chainring and get a larger gearing. I did exactly that on my Downtube folding bike (I also switched to drop bars and changed the tires). I have done some relatively fast road rides with a local group and I was in the front of the group. On my folding bike it is more effort to go fast than on my road bike, but it is definitely possible.

Wavshrdr

Almost all tires have a relationship that the higher the pressure the easier they roll. Some benefit more from being at the upper end than others. Your weight plays a factor too. I am not a small person and I run my Big Apples pretty close to 70. I have ran higher and lower and I end up keeping them between 65-75. If I am on rougher roads I air them down a little for better ride and if I am going on mostly smooth I run them at 75. I am not suggesting anyone do this as this is above the specs for the tire. Just because I've done it with no ill effects doesn't mean you will have the same situation.

Do your own roll-down testing to see what works best. Find a place where you can consistent roll down a hill without pedaling. See how far you roll at various tire pressures and determine what works best. Do a couple tests at each pressure level and see average the results. It will tell you what works best in your area.

Brian_1

n/a

jayhuse

I know my question has a ton of a variables as someone pointed out. The biggest conern is that I do not have any bike places that carry any of these bikes that I wish to buy.

Additionally, I would have to buy the bike an be stuck at a top speed of 15 mph that would not work for my commute.

After talkign to you guys an a few other posts on this biking forum I have found that I might want to consider the Cadenza. It as almost regular road bike tire along with bigger gearing.

Anyway thanks

Jay

Wavshrdr

I agree to some extent but a tire swap can make a huge difference. Today my son was riding his Downtube. It had the stock factory tires. I have ridden enough miles to know what is average pace will be. Since we aren't even doing any off-road riding I decided to put on a set of more road biased tires; a set of shaved Haro's I have for BMX trick riding. Bam! INSTANT increase in his mph average of almost 2mph if not more!!! I was riding about a 16-17mph pace and he was stuck to me like glue. He could easily break 22 mph on the flat land when he really decided to push it. Before he had a hard time even getting close to 19 mph and I never ever saw him break 20mph on the flat.

We rode close to 20 miles today and he never once said he was tired. Normally after about 10 miles he starts saying he is tired and we wrap it up shortly thereafter. Today he was actually unhappy that we stopped riding "early". The tires totally transformed the Downtube. I rode it after I had put them on and it was amazing how much more responsive the bike felt. It felt like it lost about 10lbs!

So while there are numerous variable that affect your average speed tires definitely play a big role.

geo8rge

Folders usually make compromises. Some or all of: Small wheel dia., extra weight, more flex in the frames, cheap parts. consider: https://www.sandsmachine.com/.

FWIW, Speed is more a function of your athletic/maintenance skills than the quality of the bike you started with. I could take on the winner of the tour de France if I was allowed to overhaul his hubs before the race.

james Haury

I think a better way to phrase your question is, what is the speed potential? Different tires give different potential under different conditions . A great deal depends on the engine(rider) too.

magic_magpie

To my mind, the main difference is the higher friction with higher wheel rotation frequency due to their smaller size and 20% higher drag coefficient (0.6 instead of 0.5 or 0.4 for road bike). I ride a single speed folding bike with 20'' wheels, perfectly tuned coaster hub and 53/15 gear and can reach even 30mph on flat.

downtube

Notice we moved to a 1.5" front tire for 2006. Sevaral reasons for this:
1. Rider can average 1-1.5mph faster. You actually have a push/pull force on the front/rear wheel, hence the front wheel generates more resistance (push force). Thinning it turned out to be a very good idea...while still keep the back thick for the rough stuff.
2. Lighter weight
3. It rides just as well on my MTB test rides, due to the thick rear tire. I do not recommend anyone go MTB'ing on our bikes. However, I must do so for testing purposes.

Thanks,
Yan

Fear&Trembling

I find that a fair amount of confusion and misinformation circulates regarding folding bikes and their so-called speed limitations, not only with non-cyclists (small wheels bad; big wheels good), but also with some members of the cycling community. I apportion much of this to a simple lack of understanding regarding the principles of cycling (a hpv after all) and bike technology. However, the perception that folding bikes are dramatically slower than their bigger wheeled cousins is a commonly held view. I partly ascribe this misconception (in London at least) to the hundreds of multi-modal folding bike commuters that pootle along (often for entirely understandable reasons) at sub 13/4mph. In addition, I think people tend to focus on the rather odd-looking bike (which they are less likely to do with slow moving MTBs, hybrids or racers) and as a consequence, they are more likely to associate folding bikes with slower speeds. Well, that’s my cod-associative learning theory anyway!

Notwithstanding the above, taller gears (100 gear inches +) for long, steep downhills are often lacking in folding bikes, but this is not really a problem for the vast majority of users…

DaFriMon

It might be useful to clarify the use of the term "average speed". I use this as precisely as possible, to mean the actual average speed for an entire trip that shows on my cycle computer at the end. I've noticed that some people seem to use it more vaguely, to indicate the cruising speeds they see when they're zipping along on the flats. I have no trouble cruising in the high teens to low twenties (mph) on my Dahon under favorable conditions, but then come the uphills and the headwinds to bring the average down.

The OP was also asking about a specific class of folding bike, the less expensive 8 speed models such as the Dahon Speed, or Helios, without significant mods. I'll stick to it that those will tend to be a bit slower than a decent road bike, with the same rider. Of course, if we're talking about something like a BF PRP, or a well set up Swift, or even a Dahon Speed Pro, that's something altogether different.

Trocadile

After going on a couple club rides with my 20" inch-wheeled folder, these are my entirely unscientific observations:

1) I'm at a mechanical disadvantage going downhill. This is not entirely due to my low top gear (although that is a factor), since even if we're all coasting, I'm going to be passed by the roadies.

2) Any disadvantage in the flats is slight and not an issue, although it might be if the speeds were maintained in the mid-20's (mph). Of course, this would be hard for me on any bike.

3) I have the advantage on the hills. I don't consider myself that strong a climber, but I could routinely move to the front while going up and pass those who passed me on the downhills.

Fear&Trembling

I concur with all three conclusions.

I think 1) is mainly due to aerodynamics - at high speeds the lack of drops make it harder for me to get into a good tuck.

Bacciagalupe

OK, I'm probably going to get myself in trouble by disagreeing with someone who has much more folder/bike experience than me, but....

Won't this depend on the design of the folding bike, though?

It seems like the types that fold in the middle and have long handleposts (e.g. Dahon, Downtube) will have tons of flex, which will slow you down. Plus if you use flat bars and happen to have a bike that can't adjust bar height, you're stuck in an upright position with a ton of drag. And that will make the bike mechanically (i.e. non-magically ) slower than a road bike. In exchange, you get a great fold.

From what I've heard, stiffer bikes like the Swift, BF, Moulton etc are what you need to keep up with a road bike. Maybe it's just me, but I have a hard time imagining that even the Speed Pro's will ride all that much faster than the other Dahons, except due to different (stock) tires.

The Helios and Speed P8 do have adjustable handlebars, but I can't imagine that they are anywhere near as efficient as a typical road bike. You might be able to hit 18mph on the flats, but it'd take a lot more effort than on a stiffer bike with drop bars, no?


Alrighty then... So what's the mechanical reason for 3)?

I assume that there are some technical reasons. For example, I can't really stand up in the saddle on my Dahon, so when climbing I stay in the saddle and spin. This prevents me from rocking from side to side while standing & climbing, a practice that chews up lots of power.

But I have to say, that while I can pass some people who are on road bikes whilst climbing, there are plenty who whiz right past me as well. No granny gears + very indirect chain in low gears + flat bars + flexy handlepost != zippy hill climbing. And sitting upright on a flexy bike slows me down on the flats.

In fact, hill climbing and faster speeds on the flats is one of the reasons why I'm thinking about getting a road bike....

Fear&Trembling

I guess it is connected to smaller wheels having less inertia, but I am a little out of my depth here! Hopefully someone else will clarify matters...

Trocadile

Actually, I like to stand and mash when going uphill (as long as I'm feeling vigorous) and I was comparing myself to riders who were doing the same. One of the reason I like the Downtube (in contrast to some other folders I've tried) is that it remains stable when treated this way. I definitely go slower when sitting and spinning.

As to why small wheels might have an advantage on the uphill, I believe it does have to do with overcoming inertia. My layman's understanding (probably naive) is that smaller wheels accelerate from a stop faster, and when you are fighting gravity, you are essentially repeating a similar process over and over.