More weight on the front tire
 

As a big guy, I need a lot of PSI in my tires. I'm wondering if there are people out there in favor of distributing the weight better. I know it would help me keep my PSI down a bit in back. I would think that drop handlebars and aerobars might help even it out quite a bit. It seems like this would be something considered in bike design. I imagine it is.

I'm speculating here, but I weigh 240 and I've been riding since 1970, so I get to opine:
have you considered bigger tires? I haven't used anything smaller than 32mm in years, and do most of my riding these days on 35s, around 75 psi. Grant Petersen at Rivendell says nobody over about 150 should use 23mm tires, and everything else he's said has worked for me, so I tried that. Even 28s (or Rivendell's Ruffy Tuffy in 27) help, and they'll fit many bikes.
The position change you suggest might help, but it's so fraught with potential problems (back and neck pain, for starters) I wouldn't rush into it. In the old quill stem days you could just lower the bars to see what happened, but now you need new parts.
FWIW, Grant also designs his bikes so the bars are generally level with the saddle. I was skeptical of that at first, but it cured my back and neck problems.

Aerobars will help distribute your weight forward, but as they say "there's no such thing as a free lunch." You have less control with aerobars and even many skilled riders find them unsuitable for riding in traffic or in groups.

Why exactly do you think you need to move your weight forward?

As a big guy myself (240lb, >6ft) and with a history of lower back pain due to over indulgence in contact sports back when I thought I was indestructible, I know where you're at.

After a lot of trial & error with all sorts of equipment over the years I've now finally worked out my ideal commuting/utility bike. It's a 60cm Surly LHT frame, shoulder width drop bars with the tops at saddle height, on 700x27 tires at 110psi front & rear. Also, a brooks b17 saddle, SPD clipless, and Dura-Ace 10 speed groupset (yes, on my commuter bike:thumb:).

Fatter tires than 27's at lower PSI start to fee too 'squirmish' for my liking. The 27's are fat enough to handle my weight plus a commuting load over less than perfect streets and paths, but still firm enough to let me know what's going on at the contact patch during those impromptu commuter races.:D and the weight difference starts to become noticeable (to me, at least).

Aerobars are great only if you have long uninterrupted stretches, like a freeway shoulder. I used to do a 30 mile each way commute, 25 of which was on a freeway shoulder which looked like this...

http://i187.photobucket.com/albums/x...ways/seg01.jpg

It was very nice of the engineers to separate motorized traffic from bicycle traffic with that concrete barrier all along the freeway, and to light up the cycleway like that. It made for a nice fast intersection-free commute. The aerobars were awesome for that specific commute, but I've never used them since.

I don't necessarily need to have better weight distribution. I didn't mean to give that impression to anyone. As a bigger guy, I do notice the uneven weight distribution more than the average 12lb biker. It seems to me that the back designs are very biased towards the front wheel. There's not as much weight on it, and even if there does come a big bump, I can just lift it over the obstacle.

I suppose I was more curious if anyone has considered this or read anything about it. It seems to me there would be many advantages to equal weight distribution, especially to us larger riders.

WOW that is a really nice bike path!!!

would make a 25 mile commute really nice

Don't bother. We've had big riders since the dawn of the bicycle, and outside of recumbents (but you don't want to become one of ... them... do you? ;)), there isn't anything needed beyond slightly fatter tires.

I've also just realized that putting more weight on the front wheel will make it hit bumps even harder than it does already. The back wheel gets to fly over bumps easier because the forces hitting it basically just make it pivot around your center of gravity. The bumps hitting the front almost force the axle towards your chest, so it can't deflect as easily.

I'm not sure what you mean here--all a recumbent would need was fatter tires too.... ?:|

If your weight distribution isn't 50-50 front/rear, then the tires need to be inflated proportional to the weight they're each carrying. You run into this issue more with recumbents because while some are near-equal front/rear, many are 2/3 or more on the rear--and depending on the rider, a couple could be adjusted to where they'd end up with as much as 3/4 of the weight on the rear tire. If the rear tire is inflated properly to support its load and the front is inflated the same as the rear, then the front is overinflated and will tend to have poor traction.

How much PSI is "a lot of pressure?"... For a while I was running ~25mm-wide Continentals on my recumbent, and had no issues with the tires performance. I loved how light they were, but didn't like them because they had to be inflated 120 PSI,,,, rock-hard, which transmitted a lot of road vibration. Another problem with skinny tires is that you never get a slow leak; if you get a puncture it's BOOM and then you get that clanking noise of rolling down the road on your rim. If you're going fast downhill, you can do a depressing amount of rim damage before you can safely come to a stop (assuming you can keep the shiny-side-up while stopping!).... but skinny tires have those problems no matter which kind of bike you put them on.

I do understand what the OP is saying however..... if you've ever seen pics of custom frames made for really tall people like NBA centers, the front triangle of the frame is longer, but the back end is still the same length as on any other size bike. The seatstays end up almost vertical.

It seems like a rider that much taller would need the rear end pushed out a few inches to get the same weight distribution front/rear.... And also, seems to me like they'd need cranks that were ~40% longer as well.... but nobody does that either.
~

What you would be able to lose in back (psi) you would have to add in front. So whats the difference? Riding out over aerobars on bumpy surfaces is very uncomfortable.

norwood -- hopefully the Blackshirts will bring it this week, eh?

Yeah, I hadn't thought of that. I remember wondering if it was really such a good idea to have Yao Ming's saddle almost centered over the rear hub. Although, for his, they had custom 190 mm cranks, but I imagine that if they went any longer he'd run into constant pedal strike problems in turns.

Road feel is one thing, but maintaining the right size of contact patch while avoiding pinch flats and rolling the tire off the rim is, as we know, a reason why we run such high pressures. I run my front tire lower than the rear (common recommendation is 10% difference), just like how I run different pressures on my car's tires (although the car uses a higher PSI in front because of its forward weight distribution).

I just can't make myself lighter, however. If I want less crashing and banging from my wheels, I'd need to use wider tires so that I could use a slightly lower PSI while keeping the tire safe. Further softening would have to come from the saddle choice, handlebars, and maybe the fork.

But changing the riding position to purposely put more weight on the front? Nah, I don't think that's a good idea. The bike is there to serve the rider, not the other way around. Adjust the bike to the rider, not the rider to the bike.