Lightning P-38

[Campag]

I recently acquired a Bella, and I've done a few short rides. In comparison to my P38:

- seems just as good uphill, they both have very stiff triangulated frames
- obviously a much longer wheelbase and lower bottom bracket in relation to the seat, so a larger turning circle and not as maneuverable
- my average speed on fairly hilly local rides of 20 - 30 miles seems to be the same
- very comfortable seat with mesh back and padded base. I took the padded base off my P38 seat and just use the mesh. As a result the P38 seat is a bit cooler, other than that they are both comfortable
- as it happens, the wheels and tyres are the same size (20" front, 26" rear). But different tyres, schwalbe City Jet on the rear of the P38 and marathon racer on the front, 40mm width. Marathon plus front and rear on the Bella, 47mm width. I was surprised that the wider / heavier tyres on the Bella don't seem to have made any noticeable difference although that might be the case if I was a fast rider.

[nobrakes]

That's really interesting - I'd expected the Bella to be a bit slower. Frame stiffness for the win!

[UpWrong]

I agree that weight is overrated as a determinant of speed, although a 2 Kg change is noticeable. (Roughly 2% of rider + bike). Aero is increasingly significant above 14 mph or into a headwind. Good tyres and big wheels lower rolling resistance and make a noticeable difference at all speeds. So for a slow rider like me, weight and RR are important.

But the biggest factor is being able to get the power down. This depends of relative BB and seat height, hip angle, angle of seat back and other seat factors.

The Bella has a stiff frame. It feels sporty and climbs well but overall it's slower for me than the Stratus XP and P-38. The seat might be playing a part. The Recurve seat is not my favourite. I had one on a Giro 20 too and it felt like it was absorbing power. I don't like lumbar support, I don't want any support between my hips and my upper back. Other people want their pelvis supported.

[nobrakes]

I'm not so convinced about small wheels and rolling resistance any more. I know what the physics says and I'm not arguing with it, but in real world conditions I don't see that much of a difference. As I said upthread, the P38 is 5% faster up a hill than the Pelso. It has a Schwalbe One 28 on the back (had to downsize after adding a rear mudguard) and a Schwalbe Shredda 40 on the front. The Pelso has twin 700c wheels and Pirelli PZero Race 40s front and back, running tubeless. In other words, very low rolling resistance tyres, very supple, big wheels, running at lower pressure. The physics says that the Pelso should roll faster than the P38 - but it doesn't.

This is why I am led to believe that frame flex is by far the dominant factor. I'm sure the rolling resistance of the Pelso is theoretically lower, but I think it gets lost in the noise because frame flex is just a much bigger loss. I haven't tested if it rolls faster on the flat which I have to assume it will, but after all the hills are added in the frame flex cancels out all the gains.

I have seen this on every bike I've tried - the ones that are fastest up hills are the ones that are very rigid and no mushiness (M5 CHR, Metabike Daemon, P38). Every other bike you can feel the watts being lost when you put the power down. When I sit down and think about it, it's why I feel climbing hills on some recumbents is just a real drag and not much fun. You can feel the power being bled away and it's just a frustrating experience. For me anyway!

I also get an even more exaggerated effect on our upright tandem, an Orbit Routier Pro. When I really pedal hard, it's just like all that power is disappearing into some hole. I learned it's just easier to pedal at a steady pace and not try to make the bike go faster than it will go.

BTW the One on the rear is temporary - I have had nothing but incessant punctures with them over the years. Compared to GP5000s I found the One to be a very unreliable tyre. I put it on just as a stopgap until I can get the Pirelli Cinturato 28 installed that I just bought.

[nobrakes]

I should probably stop talking down the Pelso, as I'm going to be selling it soon

[UpWrong]

I'm not so convinced about small wheels and rolling resistance any more. I know what the physics says and I'm not arguing with it, but in real world conditions I don't see that much of a difference. As I said upthread, the P38 is 5% faster up a hill than the Pelso. It has a Schwalbe One 28 on the back (had to downsize after adding a rear mudguard) and a Schwalbe Shredda 40 on the front. The Pelso has twin 700c wheels and Pirelli PZero Race 40s front and back, running tubeless. In other words, very low rolling resistance tyres, very supple, big wheels, running at lower pressure. The physics says that the Pelso should roll faster than the P38 - but it doesn't.

This is why I am led to believe that frame flex is by far the dominant factor. I'm sure the rolling resistance of the Pelso is theoretically lower, but I think it gets lost in the noise because frame flex is just a much bigger loss. I haven't tested if it rolls faster on the flat which I have to assume it will, but after all the hills are added in the frame flex cancels out all the gains.

I have seen this on every bike I've tried - the ones that are fastest up hills are the ones that are very rigid and no mushiness (M5 CHR, Metabike Daemon, P38). Every other bike you can feel the watts being lost when you put the power down. When I sit down and think about it, it's why I feel climbing hills on some recumbents is just a real drag and not much fun. You can feel the power being bled away and it's just a frustrating experience. For me anyway!

I also get an even more exaggerated effect on our upright tandem, an Orbit Routier Pro. When I really pedal hard, it's just like all that power is disappearing into some hole. I learned it's just easier to pedal at a steady pace and not try to make the bike go faster than it will go.

BTW the One on the rear is temporary - I have had nothing but incessant punctures with them over the years. Compared to GP5000s I found the One to be a very unreliable tyre. I put it on just as a stopgap until I can get the Pirelli Cinturato 28 installed that I just bought.

I guess some of my disappointed with the Giro might have been the results of frame flex rather than the seat.The tear drop shape frame tube is not noted for stiffness from an engineering POV, or so I've read. And the rear end is not triangulated,

I had the schwalbe One Evolution on my P-38. A different tyre to the One - much, much better thanks to the V-guard belt.

[nobrakes]

Another ride last night with the 160mm cranks. I'm not at one with them yet. Kept feeling like I was mashing too much and putting strain on the quads. Need more time to get used to pedalling at a higher cadence. I can waver about on steep hills though with no worries about hard interference.

I was riding at a harder level with 3 15 minute tempo intervals. One on a very gentle incline up the A7 valley, one up the main climb of the loop, and one back down the valley. Speed differential with the Pelso is starting to show - Pelso about 1.5 mph faster overall, although it's possible that the day I set that speed on the Pelso was freak weather as it did seem to be much faster than I normally go. Sometimes the air pressure and wind direction is just right. Given that there's 30 minutes of that ride with hard efforts on a mainly flat part of the route, that's kinda expected. Although given my short crank non-adaptation the actual differential might be lower when I get used to them. So the Pelso is still going to be a faster bike if giving it some welly. I'm not that interested in doing that any more though other than for training purposes!

Not sure about the Cinturato 28c yet either. It goes on much narrower than the One 28c I took off. Good puncture protection but harsher.

[nobrakes]

I was signed up for a 200 audax on Saturday but the whole family came down with some kind of bug and I was too tired to ride 20k, never mind 200. Was looking forward to testing the P38 on an audax as well, sod's law. I've been healthy all year, and the one time I want to do something is when I get ill.

Otherwise it's still going well. One slight irritation I've discovered with the Spa triple is that it puts the chain further out than the triple that was on the bike when I got it, and my leg occasionally brushes the chain on the big ring due to my wonky knees. Not sure what to do about that yet. I did try it with a pair of pedal extenders I have lying around, but then the bachetta bars it came with are too narrow and my legs hit the shifters. I like the bachetta bars, I don't want to remove them. I've ordered a set of cheap bar end thumbies and will try it with a pair of microshift bar end shifters I have in my parts bin. If I put them on the outside of the bars there might be enough space to use pedal extenders.

Always with recumbents, one small change requires multiple cascading fixes. A bit like DIY. I do sometimes miss the ease of maintenance on a DF bike.

[yostumpy]

I was signed up for a 200 audax on Saturday but the whole family came down with some kind of bug and I was too tired to ride 20k, never mind 200

I stopped booking and paying for audax quite a few years ago now, I'd get exited, I'd pay, then i'd have to bail out due to illness or something beyond my control, it got silly in the end, so I stopped.

[nobrakes]

I stopped booking and paying for audax quite a few years ago now, I'd get exited, I'd pay, then i'd have to bail out due to illness or something beyond my control, it got silly in the end, so I stopped.

Yeah I'm starting to think the same way

[yostumpy]

Re the offset chainset, see what length bb Spa recommend with it, maybe if you used your existing square taper, it’s too long, throwing the right crank further out. I have this on my Streetmachine, I fitted a Campag 175 triple and the bb is too long, as I ride, I look down at my crotch, and it’s about 8mm off center with the center tube. Can’t be bothered to change I though as the SM has chain tubes.

[nobrakes]

I got the Spa recommended BB at the same time I bought the crankset with the recommended width, so it should be fine. It's just my legs, they have a tendency to collapse inwards at the knee unless I focus on good pedalling technique at all times. I'm thinking it's probably because of the lower BB to seat height on the P38, my other bikes the chain drops away more quickly from the potential interference zone with my calf so I get away with it more easily. If I can't resolve it I'll maybe put a bit of chain tube on.

[UpWrong]

I was signed up for a 200 audax on Saturday but the whole family came down with some kind of bug and I was too tired to ride 20k, never mind 200. Was looking forward to testing the P38 on an audax as well, sod's law. I've been healthy all year, and the one time I want to do something is when I get ill.

Otherwise it's still going well. One slight irritation I've discovered with the Spa triple is that it puts the chain further out than the triple that was on the bike when I got it, and my leg occasionally brushes the chain on the big ring due to my wonky knees. Not sure what to do about that yet.

What size is the derailleur tube? Mine was a pencil with a large grommet on it that required a 34.9 mm FD clamp if I remember correctly, What BB length are you using? The usual soln to bring a chain-line in is a 110mm spindle with a road triple FD to push the chain onto the granny.

[UpWrong]

Not sure about the Cinturato 28c yet either. It goes on much narrower than the One 28c I took off. Good puncture protection but harsher.

Many years ago SJS recommended the 25/28mm panaracer pasela tourguard for their audax bikes.I've been using its successor the pasela ProTite. In 559 form, the 32-559 folding ProTite is the same width as a 28-559 folding Durano and weighs less. Might be worth trying the 32-700 folding ProTite, https://fawkes-cycles.co.uk/panaracer-p ... 0-c-p17771

[nobrakes]

Thanks for the tip. I'll take a look at that one next time.