kokomojuggler

I've been commuting all summer (10.5 miles each way, half country roads, half city) on an abandoned TREK mountain bike that I rebuilt. (New paint, new chain, pedals & shoes w/ cleats, slick tires, etc). I think the bike was made in 1992. No suspension. Anyway, I was riding home last night at about 18MPH against a slight headwind, and a group of 4 riders passed me. I tried to keep up with them (about 23MPH), but couldn't catch their draft. I'm almost 50 years old, but the guy in front of the 4 man pack is the same age as me.

Now my question. Is this because of
a) I'm a wimp (genetically challenged)
b) My mountain bike w/ 1.5"X26" slick tires is too slow
c) My pannier bags cause too much wind drag.
d) Those guys must ride much more than 100 miles/week and are in better shape.
e) Combination of above.
f) Other

I wonder how much it would be worth to get another bike. Remember, this one cost me less than $100.

I'm wondering if I should put drop handlebars on this, but I'm not sure how the shifters/brakes levers would work on drop handlebars.

Thanks.

Grim

Mountain bike=Slow

The upright riding position creates wind drag. Mountain bikes are often geared lower then a road bike. Yeah if you want to keep up with a crew then a bike with drops would help.

Javan

Had a similar thing happen last year. Not on a commute, just a 20 mile ride and a group of roadies came by me. I was at about 23 mph and they just walked past, and in about 3 minutes, they were out of site. I ride a comfort bike with a road saddle, the bars pointed forward with bar ends, pointed forward. I can get in a decent aero position, but it is in the gearing.

By the way, high speeds (20+) can be scary on a bike not meant for it!

kk4df

Sometimes it's hard to catch the draft of a fast group even when you're on a fast road bike. You have to pick up speed before they pass you, not afterwards. I've been dropped several times as I've tried to fall to the back of the paceline, especially if the one now pulling decides to pick up the pace a bit.

The mountain bike and wider tires and panniers might make 1-2 mph of difference in speed, but that's enough to drop you from a fast paceline. But keep trying to grab the end of the line if they come by again.

Danre

First, if these were road bikes and the guys were riding for fun, then you shouldn't even worry about it. You use your bike as a means of transport and cruising at 18mph is a job well done. When I first got my Allez, I already had a mtb with city tires on it and felt a difference between those and the knobbies that came on it. Nonetheless, the first time I took the Allez for a ride I thought I got a pair of wings. I guess what I am trying to say is that you should not be concerned about that situation at all.

Now, if you ask if you should get another bike, this depends on what you believe your money is worth spending on. You will surely need to spend more than $100 to get a road bike, no matter its segment. If your current bike allows you to commute safely and comfortably, then I do not see a pragmatic reason for a new bike. Still, if you wish to increase your speed slightly, or just want something fancier, then it might be worth the investment.

prawza

First of all, I generally am against drafting simply because its dangerous, especially if the ppl you draft don't know you're there.

But apart from that, the weight of the mtb is probably the greatest factor in the slowness.
Id probably vote b) and c) tho not so much the wind drag.. but moreso the weight. plus possibly e)
The dropbars will put you in a more aero position, which really.. wont make much of a difference.

Ah well.. new/or second hand roadbike will get you goin a little faster.. however they do have their downsides though. A nice hybrid, or even a lighter mtb, may even do the job.

But hey, if your bike gets you from A to B... and adds 5 extra minutes therefore giving you more exercise.. making you live longer... whats there to complain about eh?

bikinpolitico

Ah, no.

Drafting is dangerous if you don't know how to do it and the other riders don't know you are there. If you are experienced and in a group of other experienced riders, it rocks and is not particularly dangerous. Don't make generalizations like this.

ItsJustMe

In other words, the only time drafting is safe is if you're in a group and you know the others are competent. It's not safe to just come up behind a random person on the street and draft them. I've had it happen to me a couple of times. I wish they wouldn't do it, I've never ridden in a group in my life. But what the hell, if they hit my rear, they're probably going down, not me, so if they want to, I don't care that much. They can stay back there all afternoon, but it's not that safe.

bikinpolitico

I agree, plus it's rude.

e0richt

actually, on one of the organized rides here, I came up on a crowd where a biker had bumped into the person in front of her because he slowed up unexpectantly...

she went down and broke her femur in 3 places...

yeah, I think it could be called dangerous... luckily, I don't have that problem of keeping up with the group...

kokomojuggler

Thanks for the replies. I don't understand why bicycle weight makes much difference on a flat road. Once you get that weight moving, it does not require energy to keep it moving.

Are there more efficient tires than my Nashbar 1.5 X 26 street fighters? They say 60 lbs, but I've been putting in nearly 80 lbs.

If I got drop bars, would I have to get a different shifter/brake levers? Right now, they are a combo.

chephy

Probably not. 18 mph on an MTB into a headwind with panniers is quite respectable.

Probably a big factor.

Probably a factor as well.

Maybe; maybe not.

Another point to consider is that in order to catch the draft you have to accelerate pretty fast (which, for the same duration, is physically more challenging than maintaining speed you already built up), and if they already passed you, you need to accelerate to a higher speed than the speed of the group, in order to catch up.

UmneyDurak

I don't thinkt ItsJustMe says it's perfectly safe. When you ride in close proximity to other people it is somewhat more dangerous then riding by yourself. That being said drafting off total stranger who is not aware you are there, is more dangerous then riding in a group where people know they are being drafted, and have some competency level. In the example you gave, maybe the ladies competence level wasn't up to the level at which she was riding.

BroadSTPhilly

If you are asking these questions then you are already 90% of the way to a road bike. You want to be fast. You need a road bike.

på beløb

Don't worry about it. 18 mph is really quite respectable into a head wind on a MTB. Not many youngsters nowadays can keep that pace up for more than a few hundred yards. Over here in Denmark it is hazardous to close with other cycle-path users at that speed, just a little faster at 19 mph and you'd be overtaking the smaller scooters (they are limited to 30 kph).

First off, and this is often the biggest win, I would look into getting the 'correct' pressure on your tires. There is a sweet spot between too soft and too hard. There are lots of graphs about on the net that'll help you, you need to measure your tire width (don't believe what's written on the tire-wall), find your weight (be honest with yourself), with kit, and how much extra weight there is on the bike, and how it's distributed. If the tires won't allow the pressure you find, you'll have to get new tires. Generally, narrower tires will allow a higher pressure, but you'll also find from the graph you need to put a higher pressure in them. Once you get really narrow, some tires have minimum pressure too, so watch out for that. But with MTB rims that'll maybe not be an issue, as they'll have a maximum rim width too, that'll be narrower than your rims.

Next up you can get bullhorn bar-ends for your flat bar, which are meant for climbing, but I find they're also good to get into a more aero-position. i.e. on my winter bike, an old DH MTB, I have some quite long ones, set so my forearms rest on the grips when I'm holding them: aero position, but still some control.

Tsuru

Damn impressive. You should join the tour!

Bill Kapaun

If you're doing 18 MPH into a headwind with panniers, I think you need to program the correct tire size into your computer!

srmatte

tires and weight make a big difference. Road bikes are running on about 1/8 inch of rubber, you got about a full inch at least, thats a lot of resistance.

bikinpolitico

I agree. Get a road bike and never look back.

daveF

Bicycle weight will make a big difference on even a flat road. Rotating weight (wheels, tires, etc) is a bigger factor. When I ride my heavy fatter tired commuting bike with an aggressive training group, it is much harder to maintain a high speed than with my 17 pound Litespeed. Acceleration, of course is even harder with the commuter.

I'm not familiar with the Nashbar tires you are using, but going to a lightweight rim & narrow tire will make a big difference in rolling resistance.

If you go to drop bars you would have to change the brake levers/shifters and perhaps the stem as well. You're best bet if you are interested in riding with a group of roadies may be to just look into a road bike.

SlimAgainSoon

I dunno, man. Sounds like you were flying with that rig.

I don't think I could have kept up on my slicked-out MTB, and I'don't have panniers.

Grim

You be sucking at da physics.

This a a VERY old argument in auto motive circles. Skinny tires have long contact patch. Wide tires have a wide contact patch. Unless you go a sold inflexible material you will NEVER get down to anything close to 1/8 of an inch. In most cases the weigh governs the area of tire in contact with the ground and the area is not as big of a difference as one would think.

A wide tire can have the same physical area contact patch as a skinny tire. Its just if it is orented lenght wise or lateral. I run a set of Specialized 1.95 Hemisphere front (65psi)and a Cross roads rear (85 PSI) that have a very high durometer rubber. The nipples are still on the outside edges of the tires at 600 miles. At max PSI I really don't have much wider of a contact patch then my buddy does on his 700 x 27's becsue it rides up on the center of the tread. I do however have a lot more mass to spin up and the deep void tread off the locked center creates some wind drag.

Now this gets back into why weight is a big factor in speed on a bike even on flat ground. The more weight the larger the contact patch the more rolling resistance the more effort to keep keep it moving.

kokomojuggler

Thanks again for the replies. I checked my distance to work on my odometer and it matched exactly what Google maps said it would. My record time home for 10 miles is 18.2 MPH, that's with a tailwind, but also includes city traffic, where the best I can average is 15 MPH. On that ride, I was doing 26 MPH on a new smooth road and almost keeping up w/ traffic. It occurred to me that this is safer than having cars whiz past all the time.

OK I now understand that weight puts more friction on the tires. But what's a few lbs of bicycle/luggage compared to my weight of 165 lbs?

What's the real difference between a road bike and a mountain bike anyway? If I put skinny wheels/tires on a mountain bike w/ drop bars, does it become a road bike?

I had a Peugeot touring bike my parents bought me in 1971. I gave it away a few years ago. I wish I had it back!

Can you provide links?

Thanks again all!!! This is a great group.

Grim

Wind resistance is a big factor and drops would help if the bikes geometry will accommodate them. I am looking at doing the same or putting a set of aero bars on so that when I am fighting the wind I can lower my profile and when I am going slow I can have the more upright position I tend to prefer for heavy traffic where I want to see over cars.

That will get you down to gearing. I cannot peddle my bike faster then 30. That's a cadence over 100 in top gear. I like you can keep a 18-20mph pace as is. The Aero bar or drops would probably get you up to 24-25mph as a comfortable top gear pace on the flat. Beyond that you need to look at changing chain ring to get up around 50tooth. At that point you may be better off just looking for true road bike.

banerjek

You'll do much better with a road bike. Skinnier tires do help -- that is why racers use them. While it is true that the contact patch is larger than most people think, aero and weight does make a noticeable difference. For a commuter, you need a road or at least a touring bike. You will definitely notice a difference.

BTW, I've ridden more than 100 miles a week for many years, but if I can still pull 18mph into a headwind when I'm 50 on an MTB, I'll be golden. I'm not sure how long I could do that even now.