Changes to my Nazca Paseo

[UpWrong]

The new seat didn't arrive. The dutch post sat on it for a month and when an investigation was launched claimed it had an incorrect address on it! That's complete baloney. By this time the Brexit rush was well underway so I gave up and got a refund from Nazca.The intention was to try again in the spring but:

1. There is still uncertainty post-brexit and I doubt that Nazca have registered for UK sales.
2. Kevin at D-Tek didn't think the Comfort seat was likely to help and suggested reshaping the seat I have by making a pommel for it.

So just about to take a look at reshaping the seat. I have bought some tennis balls and will dig out some window windproofing seal strips. All suggestions as to how to do this welcome

[Jdsk]

So just about to take a look at reshaping the seat.
...
All suggestions as to how to do this welcome

Two part foam and a bin liner as used in karts and racing cars, eg:
https://www.cfsnet.co.uk/acatalog/CFS_Catalogue__2_Part_Polyurethane_Foam_Liquid_415.html

Jonathan

[Tigerbiten]

Because my arm harness pulls my shoulder back, I had to used a polystyrene strip across the top of my seat where my shoulders under the pad to change the shape of that part of the seat from concave to convex.
The advantage of polystyrene is you can sculpt a block to the shape you want/that works.
Once you've a shape that works then maybe a thin GRP coat over the top to reinforce it and make it more permanent.

Luck ........

[nobrakes]

I recently spoke to David at Laid Back Bikes about Nazca seats. Turns out they are made by Ocean Cycle. Maybe he can get one made for you.

[UpWrong]

So just about to take a look at reshaping the seat.
...
All suggestions as to how to do this welcome

Two part foam and a bin liner as used in karts and racing cars, eg:
https://www.cfsnet.co.uk/acatalog/CFS_Catalogue__2_Part_Polyurethane_Foam_Liquid_415.html

Jonathan

That's rather more radical than what I had in mind, which was more like extending the nose.

[Jdsk]

So just about to take a look at reshaping the seat.
...
All suggestions as to how to do this welcome

Two part foam and a bin liner as used in karts and racing cars, eg:
https://www.cfsnet.co.uk/acatalog/CFS_Catalogue__2_Part_Polyurethane_Foam_Liquid_415.html

That's rather more radical than what I had in mind, which was more like extending the nose.

I'd guess that it would work fine for extensions as well as whole seats. Attaching it securely would be the hardest part.

Jonathan

[UpWrong]

I recently spoke to David at Laid Back Bikes about Nazca seats. Turns out they are made by Ocean Cycle. Maybe he can get one made for you.

I wasn't expecting that to be the case. I think Marcin is pretty busy doing ICE carbon seats these days.

I tried sitting on the seat without a pad, and it feels very cupped even in the highest position/least reclined, but I noticed it's more difficult to get your feet down. And the edge of the seat is digging into the back of my legs. I found I had a basic camping mat style pad which saves my legs from the seat edge whilst still providing a good concave seat. So I shall give that a go tomorrow.

[UpWrong]

So, I had an exhilarating 15 mile ride- and I wasn't slding forward out of the seat . I very much noticed the lumbar support. It seemed to me that my lower back was taking much of the pressure from my pedalling. I'm used to more upright seats where it's your upper back that takes the pressure. I'll find out tomorrow if it has made me sore and stiff.

I struggled in bottom gear up the hills to keep it straight. My arms got really tense and I was losing control. I baled out on one slope. Think I might be over-reaching to the bars. I'll try rotating them a little to bring the grips slighty closer.

I have a compact double of this bike and have been on the point of reverting to a triple. However I found it ok. My strategy was to always drop to the small ring around junctions so that I could start off if i had to stop. Otherwise I stayed on the big ring when riding on the flat, or downhill. I've lost a bit of top-end compared to a triple (highest gear is 48/13) but I still wasn't maxing out on the level, and was comfortable pedalling at 21mph on slight down gradients of 1%.

The rear suspension noticeably smoothed out the ride. I've swapped out the front suspension fork for a fixed aluminium one and whilst that means you have to be wary of bad road surfaces, the rear suspension is active and does compensate to an extent.

[UpWrong]

Another 15 mile ride today after adjusting the handlebars. I was much quicker and more relaxed. I topped 30 mph on a long downhill without pedalling. Very planted in the seat even though I was only wearing a pair of jeans. Really really pleased to have found an SWB configuration that works for me. The bike's a keeper

[Tigerbiten]

I've done enough on my bent trike to work out roughly my downhill speeds while pedalling are:-
2% down ~ 20mph.
4% down ~ 30mph.
8% down ~ 40mph.
16% down ~ 50mph.
The exact speed depends a lot on headwind vs tailwind and road conditions.
20 mph on a slight downhill run is easy if no headwind.
30mph on a 4% downhill run is tricky, it either takes a tailwind or a +5% down.
40 mph on a 8% down hill run is fairly easy as long the hill is long/straight enough to risk hitting a terminal velocity.
There's not many good 16% downhills I'd risk it on so +50 mph is very rare .....

YMMV ...........

[UpWrong]

Just checked Strava. I hit 30 mph on a 2.5% descent without pedalling.

[UpWrong]

As discussed elsewhere, I need lower gears so I've replace the 40T expander cog with a 42T one. I didn't need to alter the B-screw and the chain's engagement of the cog is something like 150 degrees which should be OK. I also tested big-big on the workstand and the RD coped and was not overstressed. So the 43T specified capacity on the XT-781 RD is a bit conservative.

Since I had to take the cassette off the wheel, and since I've been thinking of trying narrower and faster tyres, I also changed the wheels for lighter ones with narrower rims. So the front went from a 24mm Halo Sub4 to an 18mm Velocity Aerohead, and the rear from a 19mm Mavic A719 to a 17mm Mavic CrossRide with aero spokes. I change the front tyre for a 50-406 Big Apple to a Maxxis 38-406 DTH, and the rear tyre from a 42mm Pasela PT to a 32mm Pasela ProTite.

The overall change is weight was 590g lighter (350g front, 240g rear). Changing the rear one might have been a mistake since the A719 had a lovely XTR hub, but I didn't think the 19mm rim was a good match for the 32 mm Pasela.

I need to go for a shakedown ride. Hoping to take it to meet up with a friend in Portsmouth tomorrow.

[UpWrong]

Shakedown Ride went well. I just had to adjust the RD top limit screw slightly. And I could cycle uphill in the new, lower bottom gear whilst going in a straight line.

[UpWrong]

I decided to go with a super compact double with chain guard. So now running 32/46 rings with the 13-42T cassette. I also found a widget to convert the MTB FD shifter to a Road cable pull to match the front SORA FD:

[UpWrong]

Gosh, interesting reading going back on my history of changes to the bike. Well, I've been at it again. I stole the 150mm triple crankset off the Paseo for the benefit of the P-38 and have replaced it with a Spa XD double with 160mm cranks and 33/48 rings. Hence I brought the boom in by 10mm. I have a 160mm XD triple but Spa say it's not 10-speed compatible whereas the XD double is. Since I used the triple as a sub-compact double it would probably have been ok with some chainring spacers fitted, but I decided to go weight weenie so went with the double and a shortish titanium axle. Gear range is 18"-90" and bottom gear on the large ring is 28", low enough for starting on flat ground. I'm quite impressed to get 500% from a double configuration using 44T capacity.

The seat is still the issue, too much lumbar support and I have to lay it back to 36 degrees to stop sliding off the front when I hit bumps. I velcro'd some camping mat above the lumbar area which has helped to transfer some of the pressure from the middle of my back to the upper back. Sometimes I feel fine and sometimes my lumbar area is still complaining. So I'm wondering if it's worth trying to find a seat with less lumbar support. AZUB make a new hardshell seat which looks promising although I assume it's glass fibre rather than carbon fibre,

It would be quite a cost and effort to change though. I'd have to drill and re-use the fittings from the current seat.

If I am going to keep the bike there is another change I'd like to make and that is to remove the return idler. The return chain line gets lifted, dragged left and then dragged right in its journey round the idler. The idler is in addition to chain tubes anyway and I reckon the double deflection and resultant friction on the chain tubes could be costing 3 or 4 watts. So I'd drop the chain but keep the chain tube. The downside is that I'd need to replace or reverse the V-brake to stop interference with the brake noodle and cable. Again, not the easiest of mods and it would be a pain to reverse it if it didn't work out.