I took the VK2 out on our club's Wednesday night ride for the first time yesterday. I had held off on the club ride up to this point until I had put a few miles on the bike and felt a little more secure riding in close quarters. As I mentioned in my last blog, by sitting up during the climbs and putting more weight on the front wheel the low speed handling improves significantly and I can climb with very little wobble down to speeds as low as 5 kph (3 mph) on very steep grades over 13%.
Our Wednesday ride starts with 10 km of gently rolling coast road before arriving at the base of the first climb. We don't usually hammer the warm up and I was coasting at 30 km for much of this distance.
The first climb is about 2.5 km at between 6% and 8%. I dragged my butt up this grade and lost 4 minutes on the better climbers; however, I've was not cycling for 6 weeks due to my neck injury so I still have lots of work to do to get my form back. The important metric is that my speed of 8 kph was 3 kph slower than my usual speed on my road bike - so not too far off considering the lack of training.
At the top of the first climb we then descend about 1000 feet on the other side of the mountain before back tracking up the same road. The grade is now a steady 8% with no flat spots to recover. Going down the mountain I quickly pulled away from the road bikes. The prospect of falling at over 80 kph had me on the brakes most the way down which raised the other fear of over heating the front wheel and blowing the tire off.
On the ascent we have one very strong climber who can hold 18 kph on the 8% grade. Needless to say he disappeared pretty quickly but I surprised myself by holding between 10 and 11 kph for most of the ascent. I guess I was finally warmed up.
Once we got back on the gentle rolling warm up road, I easily pulled away from the group and was easily able to hold between 38 and 45 kph with the occasional descent of 60 kph.
With each ride I'm becoming more convinced that the VK2's climbing performance is very close to DF. As I regain my form over the next month and get my new recumbent legs dialed in I feel confident that I will climb extremely well on this bike.
Thursday, July 31, 2008
Wednesday, July 23, 2008
Climbing on the VK2
While still nursing my road rash from my Saturday ride I headed out on Monday evening for a little climbing. We have a local 8% grade of about 1000 feet grade with a nice University at the top that is perfect for short training sessions. Like many low racers the VK2 can be set up with a narrow preying mantis tiller style handlebar configuration or a U-bar handlebar similar in shape to a city bike handlebar. I ordered the bike with the narrow tiller bar but quickly swapped it over to a U-Bar using a triathlon base bar flipped upside down on a standard 120 mm stem. This configuration allows me to sit up and pull on the bar when climbing or lay back and get more aero on the flat. Every DF rider know that you need to be able to change your body position and hip angle to climb effectively and this is certainly true on a recumbent bike too.
Another interesting issue is gearing. Recumbent riders expound about their preference for lower gearing and spin climbing. I reason that if I can comfortably climb an 8% grade on a road bike with a 39/27, I should be able to do this on a recumbent too - and in fact I found this to be the case. I like climbing with a cadence in the 65 rpm range and I found that as long as I could sit up in a more powerful position and close my hip angle I had no trouble turning this gear on my VK2.
I also found that sitting up drastically improved the low speed handling of the bike. With more weight over the front wheel the bike gets more responsive and requires smaller corrections to maintain balance. On one short 16% grade I was able to leg press my way to the top at a crawl with no instability; the bike handled amazing well as long as I was sitting up. It occurred to me that this may explain why many long wheelbase recumbents use indirect steering.
Another interesting issue is gearing. Recumbent riders expound about their preference for lower gearing and spin climbing. I reason that if I can comfortably climb an 8% grade on a road bike with a 39/27, I should be able to do this on a recumbent too - and in fact I found this to be the case. I like climbing with a cadence in the 65 rpm range and I found that as long as I could sit up in a more powerful position and close my hip angle I had no trouble turning this gear on my VK2.
I also found that sitting up drastically improved the low speed handling of the bike. With more weight over the front wheel the bike gets more responsive and requires smaller corrections to maintain balance. On one short 16% grade I was able to leg press my way to the top at a crawl with no instability; the bike handled amazing well as long as I was sitting up. It occurred to me that this may explain why many long wheelbase recumbents use indirect steering.
Crash!
I had my first crash on the weekend and am happy to report that the bike came through without a scratch. The rider has some road rash on the hip and elbow but nothing out of the ordinary for a seasoned roadie. The crash was more of a gentle 'dumping' that a crash. There was really no impact as the bike simply dumped me on the pavement as the front tire deflated. I was moving at around 40 kph at the time so I ground a fair amount of skin off my hip before I finally came to a stop. It appears that the inner tube in the front wheel cracked probably due to its aging.
In the aftermath of the crash I found myself in my freshly shredded 2XU bib shorts at the side of the road unable to remove the 20 inch Schwalbe Stelvio tire. I had to resort to the screw driver blade in my multi-tool after breaking a plastic tire lever. I applied 4 patches to the inner tube as new cracks seemed to appear each time I inflated the inner tube. Needless to say I finally had to call for backup. I have since purchased steel tire levers and will not be leaving home without them at least until I am able to build a new front wheel with a proper tubular tire. (Having raced for many years I'll never be a fan of clinchers!).
In the aftermath of the crash I found myself in my freshly shredded 2XU bib shorts at the side of the road unable to remove the 20 inch Schwalbe Stelvio tire. I had to resort to the screw driver blade in my multi-tool after breaking a plastic tire lever. I applied 4 patches to the inner tube as new cracks seemed to appear each time I inflated the inner tube. Needless to say I finally had to call for backup. I have since purchased steel tire levers and will not be leaving home without them at least until I am able to build a new front wheel with a proper tubular tire. (Having raced for many years I'll never be a fan of clinchers!).
Monday, July 21, 2008
Hello from kMike
The Velokraft VK2 is a high performance recumbent bike. I ride mainly for sport and do little commuting in any vehicle since I work online from my home office almost 100% of the time. I bought it mainly to get some relief for my neck after my doctor advised that several of the discs in my neck were in bad shape and needed a very long break from the aerobars on my tri-bike - maybe even forever! I wanted the best performing road recumbent out there and I believe I have found it.
As an engineering student back in the 80s I had been involved in several HPV projects and fell in love with the beauty, elegance and minimalist techology of cycling. To this day my favorite expression is: "less is more" followed closely by "small is beautiful"
It's been 15 years since I rode a recumbent and I was impressed to see that many of the little companies that had started out back in the 1980s were still around. I also found many new companies including Velokraft of Poland. I ended up buying a VK2 low racer from Velokraft mainly because I wanted an ultra-light, ultra-stiff carbon fibre frameset that would climb well.
Frame design
I knew as an engineer that the integrated seat on the VK2 would add a lot of lateral stiffness to the frame without affecting vertical compliance and comfort. It was also among the lightest frame sets on the market. My engineering sense is that most recumbent frames and seats are far too flexible when compared to their DF brethren and this results in greater power loss especially when climbing. To make matters worse a RWD recumbent must also transmit power across the entire length of its frame from the riders feet out in front all the way back to the rear wheel. This takes enough chain to decorate a Christmas tree and comes with about a 600 gram weight penalty. (I'm anxious to test and possibly create a FWD configuration but that will have to wait for another time.)
I also wanted a low racer layout since this appears to be most aerodynamic and will get me to the hill before my club mates. I won't be riding this bike - or any bike - in city traffic.
As an engineering student back in the 80s I had been involved in several HPV projects and fell in love with the beauty, elegance and minimalist techology of cycling. To this day my favorite expression is: "less is more" followed closely by "small is beautiful"
It's been 15 years since I rode a recumbent and I was impressed to see that many of the little companies that had started out back in the 1980s were still around. I also found many new companies including Velokraft of Poland. I ended up buying a VK2 low racer from Velokraft mainly because I wanted an ultra-light, ultra-stiff carbon fibre frameset that would climb well.
Frame design
I knew as an engineer that the integrated seat on the VK2 would add a lot of lateral stiffness to the frame without affecting vertical compliance and comfort. It was also among the lightest frame sets on the market. My engineering sense is that most recumbent frames and seats are far too flexible when compared to their DF brethren and this results in greater power loss especially when climbing. To make matters worse a RWD recumbent must also transmit power across the entire length of its frame from the riders feet out in front all the way back to the rear wheel. This takes enough chain to decorate a Christmas tree and comes with about a 600 gram weight penalty. (I'm anxious to test and possibly create a FWD configuration but that will have to wait for another time.)
I also wanted a low racer layout since this appears to be most aerodynamic and will get me to the hill before my club mates. I won't be riding this bike - or any bike - in city traffic.
Subscribe to:
Posts (Atom)